Your NaOH numbers don't transfer. Here's the KOH math.
Potassium hydroxide from the same published SAP values — times 1.4025 for the chemistry, divided by your flake's purity — then the paste, the dilution, and the bottles it actually fills. Everything stays in your browser.
The oils
Dilution
The numbers here are yours to check. This page does arithmetic on what you type — it cannot see your recipe, your equipment or your batch.
Want it to remember?
In MadeKeeper the paste is an intermediate batch with a real cost, dilution yields bottles into inventory, and every bottle knows what the oils in it cost — same as your bars already do. See for soap makers or poke around the live demo. $19/mo for the whole back office, kept for as long as you stay. The shop stays free for cost a piece and one fair — no product cap. The tax packet, Etsy and Square, and more fairs are the $19.
The KOH math bar soapers hit on night one
Every bar soaper who adds liquid soap hits the same three surprises: the factor, the purity, the dilution. The math below is the same math the calculator runs — sourced, stated, checkable.
Why can't I use my NaOH numbers for liquid soap?
Different molecule, different weight. Potassium hydroxide runs 56.1 to sodium hydroxide's 40, so every SAP value scales by 1.4025 — and then the flake in your jug is only about 90% pure, which means you need MORE of it, not less. Both corrections go the same direction, which is why a bar recipe run through a KOH batch by feel comes out lye-heavy or oil-heavy depending on which correction you forgot. The calculator applies both and says so.
Why is superfat lower in liquid soap?
Because free oil clouds it. In a bar, 5% unsaponified oil is skin conditioning; in a clear liquid soap it is haze and, eventually, rancid oil floating in the bottle. Liquid soapers run 0-3% — this page defaults to 2 — and some run a slight lye EXCESS instead and neutralize after, which is a technique choice this calculator doesn't make for you.
How much water do I dilute with?
The genuinely contested part, and the reason dilution is an input rather than an answer. Near 1:1 water to paste by weight is a common starting point, but the right ratio follows the oil profile — coconut-heavy pastes drink more water, olive-heavy less — and your own thickness preference. Dilute in stages: you can always thin a soap that is too thick, but a soap diluted too thin can only be thickened by evaporation and patience.
Where do my recipes go?
Nowhere. This runs in your browser, saves to your device's local storage, and uploads nothing. The same promise as our lye calculator, learned from Soapee — the free recipe site that shut down and took makers' saved formulations with it. Export or copy anything you want to keep.