What the builder adds to the lye calculator
The lye and water figures come from the same engine as the lye calculator, which walks through the arithmetic with a worked example and lists the lye each common oil needs. This page builds the rest of the recipe around those figures:
- Soap-quality bars for the whole blend, against the usual ranges (below).
- Fragrance as a percentage of oils; the fragrance calculator checks it against your supplier's IFRA limit.
- Cost per bar from your own prices per kilo and bar count, with packaging per bar.
- Water three ways: enter lye concentration, water : lye ratio or water as a percent of oils, and it prints the other two. The converter explains the three.
- KOH, dual lye and lye purity for liquid and shave soap, and for suppliers that assume 97% NaOH.
- A link that is the recipe, recipes saved on this device, and a one-page print sheet with the safety checklist.
What the soap-quality bars mean
The five bars are sums of the blend's fatty acids, following SoapCalc's convention so the numbers match what you are used to. Hardness is the saturated acids (lauric, myristic, palmitic, stearic). Cleansing is lauric and myristic, the short chains from coconut and palm kernel that wash oil away fastest. Conditioning is the unsaturated acids plus ricinoleic. Bubbly is lauric, myristic and ricinoleic; creamy is palmitic, stearic and ricinoleic. The shaded band on each bar is the customary range for a balanced bar; a castile sits far outside it on purpose. Iodine and INS are older single-number summaries of the same idea. They are relative indices for comparing recipes, not measurements of a finished bar. Every oil's numbers are in the oil properties chart.
The classic beginner bar (olive 35, coconut 30, palm 30, castor 5) and the same recipe with lard in place of the palm, both at 5% superfat and a 33% lye solution. The lye changes by only 0.2 g on 1,000 g of oils; the bars move more:
| Bar | Usual range | With palm | With lard |
|---|---|---|---|
| hardness | 29–54 | 45 | 42 |
| cleansing | 12–22 | 20 | 20 |
| conditioning | 44–69 | 51 | 52 |
| bubbly | 14–46 | 25 | 25 |
| creamy | 16–48 | 29 | 26 |
How cost per bar is worked out
Open Cost per bar and enter what you pay per kilo for each oil, the lye and the fragrance, plus packaging per bar. The builder multiplies each ingredient's weight in this recipe by its price, adds packaging, and divides by the bars per batch you enter. Prices stay in this browser. For labor, overhead and the price to charge, the soap cost calculator takes it from there.
Sources
SAP values, iodine, INS and fatty-acid profiles: SoapCalc oil list (https://soapcalc.net/oil-list), retrieved 2026-08-19, except where that value has been found wrong and corrected (each correction is noted on the oil). SoapmakingFriend publishes the same table. Literature ranges per oil are recorded in the engine and pinned by tests; NaOH/KOH ratio 40 ÷ 56.1. Quality-bar method and ranges: SoapCalc. Before every build, the test suite checks this calculator's arithmetic on a set of reference recipes against SoapCalc's formulas and SAP values.