Free tool

Saponification calculator

Pick your oils and weights, choose a lye type and superfat, and Saponaria computes the lye and water. SAP values are averages — read the brief and test a small batch. Making lye the old way? Try the wood-ash lye calculator. Batch gone wrong? Use the fix-it diagnostic.

Oils

Lye type

Superfat %

Water measured as

Water (% of oils)

Additives · optional

Fit to your mould · optional

Mould shape

Length (cm)

Width (cm)

Height / pour (cm)

Result

Estimate

Total oils1000 g

NaOH139.8 g

Water380 g

~ Batch1520 g

38% of oils · 26.9% lye concentration · 2.72: 1 water : lye

Predicted bar qualities

Hardness36 · 29–54

Cleansing20 · 12–22

Conditioning60 · 44–69

Bubbly lather20 · 14–46

Creamy lather16 · 16–48

Estimated from average fatty-acid profiles — guidance, not a guarantee. Always test a small batch.

Saponaria Pro adds fragrance load and bar yield, and saves recipes to your vault. See Pro →

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Your conditions

Soap behaves differently with the weather and your altitude. Check your local conditions for gel-phase and lye-temperature guidance.