Craft & Design
Superfat Percentage
What 2%, 5%, or 10% superfat actually does to your soap — cleanse vs moisture tradeoff.
Superfat Percentage
Inputs
g
0%5.0%15%
Results
Feel
Balanced — most recipes
Lye reduction
Approximate NaOH saved vs 0% superfat
7.00 g
Free oil in final bar
50.0 g
How to use this
Superfat is the percentage of oils you leave unsaponified so the finished bar has extra conditioning oil. 5% is the sweet spot for most recipes — enough to feel gentle without going rancid.
Higher superfat = softer bar and shorter shelf life. Coconut-heavy recipes (cleansing) often use 6-8% to take the edge off; pure Castile (100% olive) can sit at 3-5% because olive is already mild.
Formula
lye_reduction_g ≈ oil_g × 0.14 × (superfat ÷ 100)
free_oil_g = oil_g × (superfat ÷ 100)
Related calculators
Formula
free_oil_g = oil_g × (superfat ÷ 100)