Soap colorant calculator – mica and oxide grams per batch

The soap colorant quantity calculator works out how much mica, oxide or natural colour a batch needs, based on the weight of your oils, and gives the amount for the whole batch and per bar. Colour in soap is dosed against oil weight, usually as teaspoons per pound of oils, and the right amount depends on the colorant type and how bold you want the shade. You enter the oils, the colorant and the intensity, and the tool returns teaspoons, an approximate gram weight and a per-bar figure.

It is for soapers who want a repeatable colour instead of a pinch-and-hope approach. A pastel and a deep shade of the same mica can differ fourfold in dose, and this sets the rate before you open the jar.

Colorant is easy to overdo. Too little and the shade is muddy or faint; too much and a bold mica can bleed into neighbouring swirls or stain a washcloth. The rate chart keeps the dose in the range that colours cleanly.

✂️ How to use the soap colorant calculator

Start with the oil weight. This is the total oils in the recipe, the same base you used for lye and fragrance. Colorant is calculated on oil weight rather than total batter, so a 1000 g oil recipe uses 1000 g as its base.

Choose the colorant type. A mica, a synthetic oxide or pigment, activated charcoal and a natural clay all colour at different strengths, so the type sets the base rate the calculator works from.

Pick the intensity you want. Pastel, medium and bold map to different rates, since the same colorant gives a soft tint at a quarter teaspoon per pound and a deep shade at a full teaspoon. Medium is the sensible default for a clear, true colour.

Disperse dry colorant in a little oil before adding it, especially oxides. A teaspoon of oxide stirred straight into batter leaves speckles and streaks, while the same amount blended into oil first colours evenly.

Add the number of bars to see the per-bar amount. The dose per bar is tiny, often a fraction of a gram, which is why colour is measured for the batch and split rather than weighed bar by bar.

Read the results from the top. The hero number is the colorant for the batch in teaspoons, with an approximate gram weight beside it and the per-bar figure below. Use the teaspoons to measure and the grams as a cross-check.

Calculator fields explained

Oil weight (grams) – the total oils in the recipe, the base the colorant rate is applied to. There is no default; it comes from your recipe. Every result scales from this number.

Colorant type – mica, oxide or pigment, activated charcoal, or natural clay. Default is mica. The type sets the base rate, since oxides colour far more strongly than micas and charcoal varies with the shade.

Intensity – pastel, medium or bold, mapping to a low, standard or high rate. Default is medium. This is the field you change to go from a soft tint to a deep, saturated colour.

Number of bars – how many bars the batch cuts into, used only for the per-bar figure. Default is 12. It does not change the batch total.

📊 Understanding the results

The teaspoon figure is what you measure. A medium mica on 1000 g of oils works out to about 1.1 teaspoons. Medium mica on 1000 g of oils is about 1.1 teaspoons. You disperse that in a spoonful of oil and stir it in at trace.

The gram weight is a rough cross-check, not a precise target. Colorants pack differently, so a teaspoon of light mica weighs around 2 g while a teaspoon of dense oxide is closer to 2.5 g. If your scale reads far from the estimate, the colorant is simply lighter or heavier than average.

The rate in teaspoons per pound lets you follow supplier guidance. Most colour advice is given that way, so seeing that a medium dose is 0.5 tsp per pound lets you match a label without recalculating.

Oxides and pigments colour roughly twice as strongly as micas, so a mica rate applied to an oxide can double the colour and turn a pastel into a shade that bleeds onto skin and cloth. Always match the rate to the type, and start low with any oxide.

The per-bar figure shows why colour is a batch measurement. A gram or two spread across a dozen bars is a fraction of a gram each, far too small to weigh reliably, so you colour the whole batch and cut it into equal bars.

A very high dose, above roughly 1 teaspoon of mica or half a teaspoon of oxide per pound, is a signal to reconsider. Past that the colour rarely deepens further and the risk of bleeding, morphing or a chalky surface rises.

🧮 Calculation formulas

The dose comes from a rate per pound of oils, so the first step is turning grams of oil into pounds. Then the rate for your type and intensity multiplies out to teaspoons.

Pounds of oils = oil weight in grams / 453.6.

Batch colorant (tsp) = rate in tsp per pound x pounds of oils.

The gram estimate multiplies teaspoons by an approximate weight per teaspoon for the material, and the per-bar figure divides the batch by the bar count.

Batch colorant (g) = teaspoons x grams per teaspoon. Per bar = batch colorant / number of bars.

Work the default: 1000 g of oils is 1000 / 453.6 = 2.205 pounds. A medium mica at 0.5 tsp per pound gives 0.5 x 2.205 = 1.1 teaspoons, about 2.2 g at 2 g per teaspoon, or 0.18 g across 12 bars.

These rates are starting points, not fixed laws. A vivid mica can reach a bold shade at half the listed rate, while a weak natural colorant may need more. Colour a small test batch when a shade matters, since the same rate reads differently against a pale olive base and a cream palm base.

Grams per teaspoon vary by material, which is why the teaspoon measure is primary and the gram figure is a guide. The table below gives rough weights and the behaviour to watch for each type.

🎨 Practical examples

Each example lists the oils, the colorant, the intensity and the bars, then the dose and what the soaper does with it.

1. Standard mica colour. 1000 g oils, mica, medium, 12 bars. About 1.1 tsp, roughly 2.2 g, 0.18 g per bar. A clean, true shade for an everyday bar.

2. Pastel mica. 1000 g oils, mica, pastel, 12 bars. About 0.55 tsp, roughly 1.1 g. A soft tint for a gentle, spa-style bar.

3. Bold mica. 1000 g oils, mica, bold, 12 bars. About 2.2 tsp, roughly 4.4 g. A saturated shade, near the point where a mica may start to bleed.

4. Oxide at half the mica rate. 1000 g oils, oxide, medium, 12 bars. About 0.55 tsp, roughly 1.4 g. An oxide needs about half the teaspoons a mica does for the same depth. Start low and build.

5. Deep black with charcoal. 1000 g oils, activated charcoal, bold, 12 bars. About 6.6 tsp, which is over two tablespoons, roughly 10 g. True black needs about a tablespoon of charcoal per pound of oils. That is far more than any mica.

6. Small test batch. 300 g oils, mica, medium, 3 bars. About 0.33 tsp. Tiny amounts, which is why a pinch is so easy to overdo at small scale.

7. Natural clay colour. 1000 g oils, natural clay, medium, 12 bars. About 2.2 tsp, roughly 6.6 g. Rose clay tints and adds slip, though it can nudge the batter to trace faster.

I coloured my first black bar with a heaping teaspoon of charcoal and got a sad grey. It took a full tablespoon per pound before the soap actually looked black, and I finally stopped underdosing it.

8. Over-colouring, edge case. 1000 g oils, mica, well past bold at 2 tsp per pound. The colour does not deepen much beyond a full teaspoon, and the excess mica can bleed across a swirl and rub off onto a washcloth. More jar, no more colour.

9. Colouring a swirl. Split the 1000 g batch into two 500 g portions and dose each by its own oil share. Each half is 1.1 pounds, so a medium mica is about 0.55 tsp per portion.

💡 Tips and best practices

Disperse dry colorant in a light oil before adding it, at roughly one teaspoon of colorant to a tablespoon of oil. This breaks up clumps and spreads the colour evenly, which matters most for oxides that speckle when added dry.

Use cosmetic-grade, skin-safe colorants and confirm each one is non-bleeding if you are swirling. A craft mica meant for resin can contain colours that are not skin-safe, and a bleeding mica will blur every line in a design.

Keep a colour log with the colorant, the rate and a photo of the cured bar. Soap colour shifts between wet batter and cured bar, and only your own notes tell you what a given rate really looks like.

Start low and build toward a shade rather than dosing bold from the start. You can stir in a little more colour, but you cannot remove it, so a medium rate that you deepen is safer than a bold one you regret.

Watch for morphing colorants in cold process. Some pinks and purples turn in high-pH soap, so a colour that can morph, looking right in the bottle then shifting over the first day. Check the colorant is stable in cold process before trusting it in a design.

Account for your base colour. The rate chart assumes a pale base, and a cream or yellow batter from palm or unrefined oils mutes and warms every colour, which can need a slightly higher dose or a different shade.

Measure by teaspoon for repeatability and use the gram figure as a check. Volume is how colorant guidance is written, and a level teaspoon is more repeatable than trying to weigh a fraction of a gram on a kitchen scale.

Scale the colour with the oils. Doubling a recipe doubles the colorant, and forgetting leaves a large batch looking washed out next to your tester.

⚠️ Common mistakes to avoid

Adding colorant dry

Stirring dry oxide or mica straight into batter leaves speckles, streaks and clumps that no amount of mixing fully clears.

A teaspoon of undispersed oxide can leave dark specks through the whole bar. Undispersed oxide streaks a batch that a minute of pre-mixing would have coloured evenly. Always blend colour into oil first.

Mix the colorant into a little oil to a smooth slurry before it goes anywhere near the batter.

Using a mica rate for an oxide

Oxides colour about twice as strongly as micas, so a mica dose of oxide overshoots the shade badly.

Halve the rate for oxides and pigments, and start at the pastel end. It is far easier to add colour than to lighten an over-dosed batch.

Overdosing for a bolder colour

Past a full teaspoon of mica per pound, extra colorant stops deepening the shade and starts causing problems.

Doubling a bold mica does not make the bar twice as vivid; it makes the colour bleed and rub off. The shade plateaus while the mess grows.

Stay near the bold rate at most, and reach for a stronger colorant rather than more of a weak one.

Ignoring whether a colour is skin-safe

Not every mica or pigment sold is meant for skin, and craft-grade colours can contain unsafe materials.

Buy cosmetic-grade colorants from a soap supplier and check the skin-safe and non-bleeding notes before using them in a bar.

Forgetting the base colour

Dosing for a bright shade on a cream or yellow base gives a muted, warmed-down version of the colour you expected.

Account for the batter colour. A pale, refined-oil base takes colour truer, while a palm or unrefined base needs more or a warmer shade.

Expecting wet batter to match the cured bar

Soap colour shifts as it saponifies and cures, so the shade in the pot is not the shade on the shelf.

Judge colour on a cured test bar, not the wet batter. Some colours deepen, some fade, and only cure tells you which.

🎯 When to use this calculator

Reach for it whenever you set the colour for a batch or resize a recipe. The rate stays constant across sizes, but the teaspoons change, and this turns the rate into the amount you measure.

It matters when you switch colorant types. Moving from a mica to an oxide changes the rate by about half, and dosing the oxide at the mica rate is a common way to ruin a batch.

Use it to plan a multi-colour design. Splitting the oils and dosing each portion by its own share keeps every colour at the right strength across a swirl.

For a four-colour swirl I calculate each portion separately now. Guessing used to leave one colour dominant and another barely there, and dividing the rate by oil share fixed it.

You can skip it for a colour and batch size you make constantly and measure by habit. This tool earns its place on new colorants, resizing and designs, not on a repeat you already know.

🔗 Related calculators

• Soap lye calculator
• Superfat and lye discount calculator
• Oil blend properties calculator
• Soap mould volume calculator
• Soap fragrance usage calculator
• Soap additives calculator
• Soap batch resize calculator
• Soap cost per bar calculator

📖 Glossary

Mica – a fine shimmering colorant, cosmetic-grade for soap, dosed at a low teaspoon rate per pound of oils.

Oxide – a strong synthetic pigment that colours at about half the rate of a mica.

Pigment – a concentrated insoluble colorant, including oxides and ultramarines, used in small amounts.

Activated charcoal – a natural colorant for grey to black, needing far more than a mica for a true black.

Natural clay – a colorant like rose or kaolin clay that tints softly and adds slip to the bar.

Why do oxides need so much less than micas? Because oxides are concentrated pigment with no filler, while micas carry their colour on a lighter mineral base. The same teaspoon of oxide holds far more colouring power.

Teaspoons per pound (tsp PPO) – the usual way to state a colorant rate, counted against the oils.

Dispersion – pre-mixing dry colorant into oil to spread it evenly and avoid speckles.

Bleeding – a colour migrating out of its area into neighbouring soap, blurring a swirl.

Morphing – a colorant changing shade in high-pH soap, common with some pinks and purples.

Cosmetic-grade – a colorant tested and approved for use on skin, as opposed to craft-grade.

❓ Frequently asked questions

How much mica do I use per pound of oils?

A medium shade is about 0.5 teaspoon per pound, a pastel about 0.25, and a bold colour up to 1 teaspoon. Vivid micas reach a strong shade at less.

On 1000 g of oils, which is 2.2 pounds, a medium mica is about 1.1 teaspoons. Start there and adjust to the shade you want.

Why do oxides need less than micas?

Oxides are concentrated pigment without the mineral base that carries a mica, so they colour about twice as strongly.

Use roughly half the mica rate for an oxide, and disperse it well, since concentrated pigment speckles easily when added dry.

How do I get a true black?

Activated charcoal, and a lot of it. A true black needs around a tablespoon per pound of oils, far more than any mica dose.

On 1000 g of oils that is over two tablespoons. Less gives grey, which is why first black batches so often come out dull.

Should I measure by weight or volume?

Volume, in teaspoons, is how colorant guidance is written and is more repeatable at these tiny amounts. The gram figure is a cross-check.

A per-bar dose is a fraction of a gram, too small to weigh well, so measuring the batch by teaspoon and splitting it is the practical approach.

Why did my colour change after a day?

Some colorants morph in the high pH of fresh soap, especially certain pinks and purples, and others simply shift as the bar cures.

Check that a colorant is cold-process stable before trusting it in a design, and judge the final shade on a cured bar.

Do I dose colour on oils or total batch?

On oils, the same base as fragrance. The rate is teaspoons per pound of oils, not of the poured batter.

Oil weight is the base for colour, fragrance and superfat alike. Keeping one base for all three avoids a lot of confusion.

So a 1000 g oil recipe uses 2.2 pounds as the multiplier regardless of how much the batter weighs.

Can I use food colouring or craft colours?

No. Food colours fade or vanish in the high pH of soap, and craft-grade colorants may not be skin-safe.

Use cosmetic-grade micas, oxides and clays from a soap supplier, and check each is approved for skin and non-bleeding.

How do I colour a multi-colour swirl?

Split the oils into portions and dose each by its own share. A 500 g portion of a 1000 g batch is 1.1 pounds, so it takes about half the batch dose.

Calculating each portion separately keeps every colour at full strength. A 500 g swirl portion takes about 0.55 teaspoon of medium mica.

⚖️ Disclaimer

This calculator provides educational estimates for colorant dosing in soap. It is a planning aid for hobby and small-batch soapers, not a substitute for the guidance supplied with each colorant.

Colour strength varies widely by material and brand, so the rates and gram weights here are approximations. A vivid colorant may need less and a weak one more, and the same rate reads differently against different bases.

Use cosmetic-grade, skin-safe colorants and follow the supplier’s instructions. Confirm a colorant is approved for skin and, for swirls, that it is non-bleeding.

Soap making uses caustic lye. Wear eye protection and gloves, work in ventilation, add lye to water rather than water to lye, and disperse colorants carefully to avoid inhaling fine powders.