Choose oils, set lye and water, then save, export or email the recipe summary. Advanced oil data and optional additions remain available when you need them.
02
Added oils
Oil / butterWeight (g)
Total oils1,000.0 g
03
Lye + water settings
NaOH hard-bar profileAmounts are calculated automatically from the selected oils.
Superfat
5%
Lye concentration
33%
NaOH purity
97%
Fragrance load
3%
04
Advanced maker targets
These calculated target amounts update with your oil batch and are locked. Citric acid needs the shown extra lye; add it only when you use citric acid.
IngredientTarget amount
Fragrance / essential oil3% of oils30.0 g
Sodium lactate (60%)2% of oils20.0 g
Sodium citrate1.5% of oils15.0 g
Tetrasodium EDTA0.5% of oils5.0 g
Rosemary oleoresin (ROE)0.1% of oils1.0 g
Citric acid powder1% of oils10.0 g
Extra NAOH for citric acidRequired lye adjustment6.4 g
Custom powders, liquids & infused oils
Optional notes only — you can edit these, and they never change the lye, water or oil calculation.
Formula analysis
Soap properties
Indicative values derived from the selected oils’ typical fatty-acid profiles. Target values help guide a balanced cold-process bar.
Hardness
38
Target 38–45
Cleansing
20
Target 12–16
Conditioning
58
Target 52–62
Bubbly
20
Target 18–25
Creamy
18
Target 20–30
Longevity
18
Target 20–30+
Iodine67
INS146
Cold-process balance is within the practical range
For a stable hard bar, aim for Iodine 50–65 (keep below 70) and INS 145–160. A luxury blend is usually best at Iodine 55–62, INS 145–155 and 5–7% superfat.
Cold-process bath soap guide
Balanced, premium bar targets
Use these as practical formulation targets; do not chase one number at the expense of the overall oil blend.
HardnessTarget 38–45
CleansingTarget 12–16
ConditioningTarget 52–62
BubblyTarget 18–25
CreamyTarget 20–30
LongevityTarget 20–30+
Hardness and longevity: use palm, coconut and butters to retain a firm, long-lasting bar.
Sunflower: keep regular sunflower around 10–15%, unless using high-oleic sunflower oil.
Lather: if bubbly lather is low, a small increase in coconut or castor oil can help. Allow a full 5–6 week cure for softer, conditioning blends.
Fatty-acid profile
Lauric14.4%
Myristic6.0%
Palmitic14.9%
Stearic3.0%
Ricinoleic0.0%
Oleic41.4%
Linoleic15.6%
Linolenic1.0%
Read before making soap
⚠︎
Lye is corrosive. Calculation is only one part of safety.
Wear suitable eye protection, gloves and protective clothing. Work in a ventilated, interruption-free area away from children and animals.
Always add lye slowly to water—never pour water into lye. Use heat-safe, lye-compatible equipment and an accurate scale.
SAP and fatty-acid values vary by source and batch. Verify the supplier assay, selected SAP values, formula and method independently before production. This calculator is a planning aid, not a tested recipe.
