Acrylic Drying Time Calculator – Know When to Recoat

Acrylic paint feels dry long before it is dry, and that gap is where most ruined paintings happen. This calculator takes the thickness of the layer you just laid down, the temperature of the room, and the relative humidity, and returns three numbers: how long until the surface is touch dry, how long until you can safely put another coat on top, and how many days until the film has fully cured. It is built for painters, rock painters, furniture upcyclers, and anyone who has lifted a layer of half-dry acrylic with a brush and had to start over.

The three inputs are the only ones that matter for a first-order estimate, and they are the three most people ignore. A thin wash in a warm dry studio is touch dry in about ten minutes. The same paint, laid thick in a cold damp shed, needs an hour and a half. That is a ninefold spread from the same tube of paint, and no drying time printed on a label can account for it.

What the calculator does not do is guess at your brand, your medium, or your substrate. Golden Heavy Body on gessoed canvas behaves differently from a craft acrylic on a sealed river rock. Treat the output as a planning number: it tells you whether to go and make coffee or go and do something else for the rest of the afternoon.

✂️ How to use the Acrylic Drying Time calculator

Start with the paint layer selector, because it drives everything else. The three options map to three base times built into the tool: a thin wash or ordinary brush coat gets a base of 20 minutes, medium body gets 45 minutes, and thick impasto gets 120 minutes. Those base figures assume a reference condition of 21°C and 50% relative humidity, which is roughly a heated indoor studio in spring.

Lisa Mandel

Pick honestly. The most common misuse is selecting "thin wash" because the paint was diluted, when in fact three diluted coats were flooded on wet-on-wet and the total film is closer to medium body. The selector is asking about the thickness of the film sitting on the surface right now, not about how watery the paint was in the palette.

Next, enter the room temperature in degrees Celsius. The default is 21. The calculator does not read your thermostat setting, it reads the air where the painting actually sits, and those two numbers are often five degrees apart if the piece is drying on a floor, near a window, or in an unheated back room. A cheap digital thermometer parked next to the work is worth more than any drying chart.

Measure temperature at the painting, not at the wall thermostat. Air near a cold exterior wall or on a concrete floor commonly sits 3 to 6 degrees below room average, and at 15°C instead of 21°C the calculator adds 18% to every drying number.

Then enter relative humidity as a percentage. The default is 50. If you have no hygrometer, a heated home in winter usually runs 30 to 40%, a normal room in a temperate climate sits near 50 to 60%, and a bathroom, basement, or a coastal room in summer can hold 70 to 85%. Guessing within ten points is fine, because the humidity factor moves by only 1% per percentage point.

Read the results left to right in the order they appear. The touch dry figure is the headline number in minutes. Below it, the recoat time, also in minutes, is exactly double the touch dry figure in every case. At the bottom, full cure is given in days, and that is the number that governs varnishing, framing, stacking, shipping, and anything involving pressure on the surface.

Recalculate whenever a condition changes. Turning on a dehumidifier in a 75% room and dropping it to 45% cuts drying times by about a fifth. Opening a window in January can double them. The tool costs nothing to re-run, so re-run it rather than trusting the number you got yesterday.

📋 Calculator fields explained

Paint layer – a three-option dropdown that sets the base drying time. “Thin wash / brush coat” uses a base of 20 minutes touch dry and 3 days to cure, and covers glazes, washes, underpainting, and any coat you can still see the weave or the substrate through. “Medium body” uses 45 minutes and 7 days, and covers a standard opaque coat straight from the tube or bottle, applied with a brush and levelled out. “Thick / impasto” uses 120 minutes and 21 days, and covers palette knife work, heavy texture medium, poured pools, and anything where the paint stands proud of the surface. The default selection is thin.

Room temperature (°C) – a number field with a step of 1, defaulting to 21. This is the ambient air temperature of the space where the piece is drying, in Celsius. It feeds a factor that increases drying time by 3% for every degree below 21 and decreases it by 3% for every degree above. The factor is clamped to a range of 0.5 to 2, which means it stops responding below roughly minus 12°C and above roughly 38°C.

Relative humidity (%) – a number field with a step of 1, defaulting to 50. This is the relative humidity of the same air, as a percentage. It changes drying time by 1% for every percentage point away from 50: drier air speeds drying, damper air slows it. The factor is clamped to a range of 0.6 to 1.8, so it bottoms out at 10% humidity and, in practice, tops out at 1.5 when you enter 100%.

📊 Understanding the results

The touch dry number is the one people watch, and it is the least consequential of the three. It tells you the top skin has formed. Under that skin, in a medium body layer, the paint is still soft enough that a stiff brush loaded with fresh colour will drag it up and turn your clean edge into mud.

Recoat time is fixed at double touch dry by design. It is a deliberately conservative rule of thumb rather than a separate physical model, and it holds up well across the three thickness classes. If your touch dry reads 39 minutes, the tool gives you 78 minutes to recoat. Waiting longer never hurts an acrylic film. Waiting less than the number is where the trouble starts.

Touch dry is not recoat ready and recoat ready is not cured. A medium coat at 21°C and 50% humidity is touch dry in 45 minutes, recoatable in 90 minutes, and cured in 7 days. Varnishing on day 2 traps water in the film and produces a cloudy, milky bloom that cannot be removed without stripping the varnish.

Full cure is the number that protects your painting, not touch dry. Everything irreversible happens on the cure timeline: isolation coats, varnish, glass contact, shipping in a tight sleeve. The calculator gives cure in days with one decimal place, so a reading of 6.1 days means “start of day seven”, not “sometime this week”.

Edge cases behave predictably once you know the clamps. Enter a temperature of 40°C and the temperature factor pins at 0.5, so a thin wash reads 10 minutes touch dry no matter how much hotter the room gets. Enter 5% humidity and the humidity factor pins at 0.6. Beyond those limits the model has stopped tracking reality anyway, since paint drying above about 35°C starts skinning over so fast that the film cracks.

The two factors multiply, which is why cold and damp together is so much worse than either alone. At 15°C the temperature factor is 1.18. At 75% humidity the humidity factor is 1.25. Together they give 1.475, so a medium coat that normally takes 45 minutes now takes 66 minutes and its cure stretches from 7 days to 10.3.

Very low readings deserve suspicion. If the calculator tells you a thick impasto layer will be touch dry in 92 minutes, that refers to the outer millimetre. A 5 mm palette knife ridge can stay soft in its core for weeks, and the tool’s 21 day base for thick layers already reflects that. Trust the cure figure over your fingertip.

Conversely, a very high reading (say a thick layer at 5°C and 85% humidity, giving 90 minutes touch dry and 14 days cure) should be read as a warning rather than a schedule. Below about 10°C most acrylic emulsions cannot coalesce properly at all, and the film that eventually forms is weak and chalky regardless of how long you wait.

🧮 Calculation formulas

Three lines of arithmetic drive the whole tool. The first picks a base time from the thickness selector. The second and third build correction factors from temperature and humidity, and everything is multiplied together.

tempFactor = clamp(1 + (21 - temperature) × 0.03, 0.5, 2)

humidityFactor = clamp(1 + (humidity - 50) × 0.01, 0.6, 1.8)

touchDry = baseMinutes × tempFactor × humidityFactor

recoat = touchDry × 2

fullCure = baseDays × tempFactor × humidityFactor

Both base columns are read at the reference point of 21°C and 50% humidity, where both factors equal exactly 1. That is why a thin coat at the defaults returns 20 minutes, 40 minutes, and 3.0 days with no arithmetic at all.

Temperature has three times the leverage of humidity, point for point. Raising a room from 18°C to 24°C removes 18% of the drying time. Dropping humidity from 60% to 54% removes 6%. If you can only fix one variable, fix the heat.

Here is a full walkthrough. Medium body coat, room at 24°C, humidity at 45%. Temperature factor: 1 + (21 – 24) × 0.03 = 1 – 0.09 = 0.91. Humidity factor: 1 + (45 – 50) × 0.01 = 1 – 0.05 = 0.95. Product of the two factors: 0.8645. Touch dry: 45 × 0.8645 = 38.9, displayed as 39 minutes. Recoat: 77.8, displayed as 78 minutes. Full cure: 7 × 0.8645 = 6.05, displayed as 6.1 days.

Notice that the same pair of factors applies to the cure figure. The tool assumes cure scales with the same environmental physics as surface drying, which is a simplification, but the ordering it produces (warm dry room cures faster than a cold damp one) is the part you act on.

🎨 Practical examples

1. Underpainting on canvas, studio at default conditions. Thin wash, 21°C, 50%. Both factors are 1. Touch dry 20 minutes, recoat 40 minutes, cure 3.0 days. You block in the composition, take a 40 minute break, and come back to lay in the first opaque passage without lifting anything.

2. Painted rocks on a summer patio. Thin coat, 30°C, 20% humidity. Temperature factor 0.73, humidity factor 0.70, product 0.511. Touch dry 10 minutes, recoat 20 minutes, cure 1.5 days. You can run a batch of twelve rocks and be back at the first one before the paint on it is fully hard. Sealing on day two is fine.

3. Furniture upcycle in a heated living room. Medium body, 22°C, 55%. Temperature factor 0.97, humidity factor 1.05, product 1.0185. Touch dry 20 minutes on a thin primer and 46 minutes on the medium coat. For the medium coat: recoat 93 minutes, cure 7.1 days. Two coats fit comfortably in an evening; the piece should not carry a lamp until the following week.

4. Cold garage session in October. Medium body, 15°C, 75% humidity. Temperature factor 1.18, humidity factor 1.25, product 1.475. Touch dry 66 minutes, recoat 133 minutes, cure 10.3 days. You get two coats into a four hour session instead of the four coats you planned.

Before committing a whole evening, run your actual room numbers once and compare the recoat figure against the time you have. A session that fits three coats at 24°C fits one and a half at 15°C, and there is no technique that closes that gap.

5. Palette knife impasto, reference studio. Thick, 21°C, 50%. Touch dry 120 minutes, recoat 240 minutes, cure 21.0 days. This is the classic case where the surface lies to you. The ridges feel firm after two hours and stay soft underneath for three weeks.

6. Craft fair production run of small canvases. Thin, 28°C in a warm workshop, 35% humidity. Temperature factor 0.79, humidity factor 0.85, product 0.6715. Touch dry 13 minutes, recoat 27 minutes, cure 2.0 days. With a 27 minute cycle you can run a rotation of about eight boards and keep your hands busy continuously.

7. Selling work that ships next week. Thick impasto, 26°C, 40%. Temperature factor 0.85, humidity factor 0.90, product 0.765. Touch dry 92 minutes, recoat 184 minutes, cure 16.1 days. Sixteen days of cure on a piece a buyer wants shipped in five. Either you change the paint layer, or you tell the buyer the truth, or you ship a painting that will bloom under its varnish and print the packing foam into its surface.

8. Unheated shed in early spring. Medium body, 5°C, 85% humidity. Temperature factor 1.48, humidity factor 1.35, product 1.998. Touch dry 90 minutes, recoat 180 minutes, cure 14.0 days. The numbers double against reference conditions, and at 5°C the film quality itself is compromised. Move indoors.

9. Edge case, extreme clamping. Thin coat entered at minus 20°C and 5% humidity. The temperature factor pins at its maximum of 2 and the humidity factor pins at its minimum of 0.6, giving a product of 1.2. Touch dry 24 minutes, recoat 48 minutes, cure 3.6 days. The arithmetic is well behaved; the physics is not, because acrylic emulsions do not coalesce below freezing at all. Read a clamped result as a signal that you have left the model’s useful range.

10. Material substitution, thick to thin. You planned an impasto sky at 21°C and 50% (120 minutes touch dry, 21 days cure) but the deadline will not allow it. Switching to three thin glaze layers gives 20 minutes touch dry each, 40 minutes between coats, and 3.0 days cure. Total working time for three coats is about two hours instead of one, and the cure drops from three weeks to three days.

💡 Tips and best practices

Buy a combined thermometer and hygrometer and leave it on the drying shelf. They cost less than one tube of artist grade phthalo blue and they turn every number this calculator produces from a guess into a measurement. Without one, you are entering the temperature you wish the room was.

Heat first, dehumidify second. Because the temperature coefficient is 0.03 per degree and the humidity coefficient is 0.01 per point, a small heater does three times as much work per unit of change as a dehumidifier does. In a cold damp room, running both is still the right answer.

Do not aim a hair dryer or heat gun at wet acrylic to force the numbers down. Forced air skins the surface while the underlayer is still mobile, which produces wrinkling on medium coats and cracking on impasto. Warm the room, not the paint.

Keep a written log for repeat work. If you paint the same product every week, record the thickness class, temperature, humidity, and the actual observed touch dry time for a month. You will quickly learn whether your paint runs faster or slower than the model, and by roughly what percentage.

When a project mixes layer types, calculate each one separately. A thin underpainting followed by a medium body midground followed by thick highlights has three different clocks running, and the last one you apply sets the cure date for the whole piece.

Airflow is not in the model, but it is real. Gentle ambient circulation from an open door or a slow ceiling fan speeds drying by moving the saturated boundary layer away from the surface. Treat it as a bonus, not something to build a schedule around.

The single most useful habit: recalculate cure, write the date on a piece of masking tape, and stick it to the back of the stretcher. Nobody forgets a date written on the frame; everybody forgets one they calculated three weeks ago.

For anything you intend to varnish, add a margin on top of the cure figure. The calculator’s 7 day medium body cure at reference conditions is a working minimum. Most varnish manufacturers, including Golden and Liquitex, specify a minimum of two weeks before varnishing, and they are describing a thin film in good conditions.

Stack, wrap, and box only after cure. Acrylic remains slightly thermoplastic and tacky for its whole cure period, which is why a painting that felt perfect at day 3 comes out of its bubble wrap on day 5 with a permanent hexagonal texture printed into the sky.

If you work in a humid climate year round, standardise on thin layers and build up. Four thin coats at 80% humidity give a touch dry of 26 minutes each and a cure of 3.9 days. One medium coat in the same room gives 59 minutes and 9.1 days, for less total colour.

Retarders and open mediums invalidate the numbers in one direction only. Adding an open medium to keep the paint workable can extend touch dry by 50% or more, and none of that is in the model. Adding water does not speed the cure of the film, it only thins it.

⚠️ Common mistakes to avoid

Treating touch dry as permission to varnish

This is the mistake that destroys finished work. The touch dry figure describes a skin a fraction of a millimetre thick. Underneath, water and coalescing solvent are still leaving the film, and varnish applied on top seals them in.

Varnishing before full cure produces a milky white haze that appears days later, when the trapped moisture reaches the varnish layer. Removing it requires solvent stripping of the varnish, which on a thick acrylic film usually damages the paint underneath.

Read the cure field, add a margin, and put the date somewhere you will see it. Varnishing three weeks early is the most expensive mistake on this list.

Choosing “thin” because the paint was watery

Dilution and film thickness are separate things. Three watery coats flooded on wet-on-wet build a film that behaves like a medium body layer, and the model’s 20 minute base will underestimate your drying time by more than half.

Look at the surface and ask whether the paint stands above it. If a raking light throws a shadow off the edge of a brushstroke, that is not a thin coat.

Entering the thermostat setting instead of the air temperature

A thermostat on an interior hallway wall can read 21°C while the corner of the studio where your canvas leans against a north wall sits at 16°C. That five degree difference is a 15% increase in every result the calculator gives you.

Put the thermometer where the painting is, at the height the painting is. Floor level in an unheated room is routinely the coldest air in the building.

Ignoring humidity because it is invisible

Humidity does less than temperature per point, but it moves over a much wider range in ordinary life. A winter room at 30% and a summer basement at 80% differ by 50 points, which is a factor of 0.80 against 1.30, or a 63% increase in drying time.

The worst version of this mistake is painting in a bathroom because the ventilation seems adequate. A bathroom that has recently been used sits at 80 to 95% relative humidity for an hour afterwards, which is where the humidity factor climbs to 1.45.

If you cannot control the room, at least measure it and let the calculator tell you what the room is costing you.

Recoating on the touch dry number instead of the recoat number

The recoat figure exists because a brush loaded with fresh acrylic and pressed into a partially dry film will lift it. The result is a torn edge or a smear of the layer below into the layer above.

The gap is not trivial. A medium coat at 15°C and 75% humidity is touch dry at 66 minutes and recoat ready at 133 minutes, which is more than an hour of waiting that people routinely skip.

Assuming thick layers cure proportionally to thin ones

Thick is not just slower, it is disproportionately slower, and the model reflects that: 3 days for thin, 7 for medium, 21 for thick. Cure time scales roughly with the square of film thickness in real polymer films, which is why the jump from medium to thick triples the days rather than doubling them.

If a schedule cannot absorb 21 days, redesign the surface rather than hoping the paint cooperates.

Forcing dry with heat guns and hair dryers

A heat gun raises the surface temperature well past the point the model covers, and the temperature factor is clamped at 0.5 for a reason. The skin sets while the body of the paint is still moving, and the trapped stress shows up as wrinkles or hairline cracking.

A warm room at 26 to 28°C achieves most of the same speed benefit safely, giving a factor of 0.85 to 0.79 with no thermal shock.

Stacking or shipping on the touch dry timeline

Acrylic stays slightly tacky throughout its cure, and pressure against a partially cured film transfers texture permanently. Foam, bubble wrap, and glazing all leave marks.

Use the cure figure as your shipping gate, and if the number is 16.1 days, tell the buyer 18 rather than discovering the problem after the courier has been.

🕒 When to use this calculator

Open it whenever the schedule and the paint are in conflict. A commission with a delivery date, a market stall next weekend, a batch of forty painted rocks that all need sealing, a mural you can only reach on Saturdays: in every case the recoat number decides how many layers actually fit in the time you have, and the cure number decides whether the piece can be handed over at all.

It earns its keep hardest in unheated or seasonal spaces. Garages, sheds, balconies, and basements swing across 20 degrees of temperature and 50 points of humidity over a year, and the same painting routine that worked in July fails in November for reasons that feel mysterious until you see a factor of 1.48 next to a factor of 1.35.

Nobody ever ruined a painting by waiting an extra day. The calculator exists to tell you which days you are allowed to skip, not to give you permission to hurry.

It also has a planning use before you touch a brush. If you know a piece must ship in ten days, run the thick option first: 21 days at reference conditions kills the plan immediately, and you can redesign toward layered medium body work before you have committed any paint.

There is no point opening it for a single thin wash in a normal room that you will not touch again for a week. The answer is 20 minutes, the wash will be dry long before you return, and the cure figure of 3 days will pass unnoticed. It is also the wrong tool for oils, alkyds, enamels, and epoxy resin, all of which cure by chemistry the model does not describe.

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📖 Glossary

Touch dry – the point at which a light fingertip on the surface no longer picks up wet paint. It describes the top skin of the film only.

Recoat window – the time after which a fresh wet layer can be applied without lifting or dragging the layer beneath. In this calculator it is fixed at twice the touch dry time.

Full cure – the point at which the acrylic polymer has finished coalescing and the film has reached its final hardness and water resistance.

Coalescence – the process by which acrylic polymer particles suspended in water fuse into a continuous film as the water leaves. It stops working below roughly 10°C.

Relative humidity – the amount of water vapour in the air as a percentage of the maximum that air can hold at that temperature.

Why does warm air dry paint faster if the humidity number stays the same? Because relative humidity is relative to temperature. Warm air holds more water, so at the same percentage it has more capacity left to absorb what leaves the film, and the molecules on the surface have more energy to escape with.

Impasto – paint applied thickly enough to stand above the surface and hold the mark of the brush or knife.

Open medium – an additive that slows acrylic drying to extend blending time. It lengthens touch dry beyond anything this calculator models.

Retarder – a glycol-based additive with the same purpose as an open medium, usually recommended at no more than 15% of the paint volume.

Isolation coat – a permanent layer of clear acrylic medium applied over the cured painting and beneath the removable varnish, to protect the paint if the varnish is ever stripped.

Varnish bloom – the milky haze that appears when varnish is applied over an uncured film and traps moisture behind it.

Clamp – a limit that stops a calculated factor going beyond a set range. Here the temperature factor is clamped to 0.5 to 2, and the humidity factor to 0.6 to 1.8.

Base time – the drying figure the calculator starts from before applying environmental factors: 20, 45, or 120 minutes depending on layer thickness.

Medium body – a paint consistency that holds a soft peak, roughly that of thick yoghurt, applied as an opaque brush coat.

Film thickness – the depth of the dried paint layer measured perpendicular to the surface. The single largest driver of cure time.

❓ Frequently asked questions

Why is recoat time always exactly double touch dry?

The calculator uses a fixed 2x rule rather than modelling recoat separately. It is a conservative safety margin that works across all three thickness classes.

In practice the true safe recoat point varies with the paint brand and the substrate, but doubling has the advantage of scaling automatically with conditions. In a cold damp room where touch dry stretches to 90 minutes, the recoat figure stretches to 180 with it.

Can I varnish once the calculator says the paint is cured?

The cure figure is the earliest reasonable date, not a recommendation to varnish that morning. It represents the point at which the film has done the bulk of its coalescing.

Most varnish manufacturers specify a minimum of two weeks for a thin film. If the calculator gives you 3.0 days for a thin coat, take that as the moment the surface is stable and still wait the manufacturer’s period before varnish goes on.

Does the calculator work for craft acrylics as well as artist paints?

The physics of water leaving an acrylic emulsion is the same in a two dollar craft bottle and a professional heavy body tube, so the ordering of the results holds for both.

Craft acrylics generally carry more water and less pigment, so a single coat is usually a thin coat in this tool’s terms, giving 20 minutes touch dry and 3 days cure at reference conditions.

What temperature should I enter for outdoor work?

Enter the actual air temperature in the shade at the surface you are painting, not the forecast high. A wall in direct sun can run 15 degrees above ambient, which pushes the temperature factor past the 0.5 clamp and into territory where the paint skins too fast.

Outdoor humidity also swings enormously between midday and evening. A 40% afternoon can become an 85% dew-heavy night, which raises the factor from 0.90 to 1.35, and any coat still soft at dusk will take half again as long as you planned.

Why does my thick layer feel dry in an hour when the tool says 120 minutes?

Your fingertip is testing the skin. Impasto forms a firm outer shell quickly and stays soft in its core for a long time, which is why the model’s cure base for thick paint is 21 days rather than 7.

Press the edge of a ridge with a fingernail rather than a fingertip. If it dents, the film underneath is still mobile.

What happens if I enter a humidity above 100?

The field accepts any number, and the humidity factor keeps rising until it hits its clamp of 1.8. Relative humidity above 100% is not physically meaningful for air in a room, so the numbers you get are arithmetic rather than prediction.

The highest factor you can produce with a real reading is 1.5, at 100% humidity. That means a medium coat at 21°C would take 68 minutes to touch dry and 10.5 days to cure.

Does a fan speed up drying?

Airflow removes the saturated layer of air sitting immediately above the paint film, which does help, but it is not part of the calculation.

Gentle circulation is safe. A fan aimed directly at wet paint can drive dust into the surface and skin it unevenly, and the effect on a thick layer is closer to a heat gun than to a warm room.

The safest speed-up is the least dramatic one: raise the room to 25°C, drop humidity to 40%, and let the paint alone. Those two changes together give a factor of 0.88 times 0.90, which is 0.79, cutting a 45 minute touch dry to 36 minutes with no risk to the film.

Why does the cure figure use the same factors as touch dry?

The tool applies the same temperature and humidity multipliers to the base cure days that it applies to the base minutes. It is a simplification, since deep cure depends more on diffusion through the film than on surface evaporation.

The direction it gives you is right: a cold damp room really does slow cure, and the relative ordering between thin, medium, and thick is where the practical value sits.

Can I paint acrylics in an unheated room in winter?

You can enter the numbers, but below roughly 10°C the emulsion cannot coalesce properly and the film that forms is weak and chalky no matter how long you leave it.

Below 10°C the film never reaches full strength, however long you wait. The calculator will happily give you a cure figure of 14 days at 5°C, and that number describes drying, not a good painting.

How accurate are these estimates?

They are planning estimates built on three variables, and they ignore brand, medium, substrate absorbency, airflow, and additives. Expect the touch dry figure to land within about 30% of reality for a standard acrylic on a primed surface.

Log your own results for a month against the tool’s predictions and you will find your personal correction factor. If your paint consistently runs 20% slower, add 20% to every number and the tool becomes accurate for your studio.

Does the substrate change the drying time?

Yes, considerably, and the calculator does not model it. Absorbent surfaces such as raw wood, unsealed terracotta, or paper pull water out of the paint from below and can halve the touch dry time.

Sealed surfaces such as glass, plastic, and heavily gessoed canvas leave all the water to escape upward, which pushes the real touch dry above the number the tool gives you.

Should I use this for pouring or resin work?

Poured acrylic is a thick layer by any definition, so the thick option and its 21 day cure base is the nearest fit. A pour containing pouring medium will run slower still.

Epoxy resin is a different chemistry entirely, since it cures by reaction rather than by water leaving a film. Nothing in this calculator applies to it.

⚖️ Disclaimer

This calculator provides educational craft-planning estimates. The figures it returns are derived from three inputs and a simple multiplicative model, and they cannot account for paint brand, pigment load, binder chemistry, substrate absorbency, airflow, additives, or the total number of layers already on the surface.

Drying and curing behaviour varies between manufacturers and between colours within the same range. Where a paint or varnish manufacturer publishes a minimum drying or curing period, that figure takes precedence over anything produced here.

No output from this tool constitutes business or financial advice, and no scheduling decision with money attached should rest on it alone. If a commission, a shipment, or a client deadline depends on a cure date, build a margin into the date you promise.

Test on a sample before committing expensive materials. A scrap board painted with the same layer thickness, dried in the same room, and checked at the times the calculator predicts will tell you more about your own conditions than any general model can.