Bars of Soap
11
Lye
4.62 oz
Milk
1.4 cups
Cost/Bar
$0.92
Estimated Bars
11
48.2 oz total batch
Hardness
42
Conditioning
53
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Inputs
Result
Olive: 19.2 oz x 28.35 x 0.134 = 72.9 g NaOH. Coconut: 12.8 oz x 28.35 x 0.1787 = 64.9 g NaOH. Total: 137.8 g x 0.95 (5% superfat) = 130.9 g = 4.62 oz lye. Milk: 4.62 x 2.5 = 11.5 oz.
Inputs
Result
Tallow: 28.8 oz x 28.35 x 0.1405 = 114.7 g. Shea: 19.2 oz x 28.35 x 0.128 = 69.7 g. Total: 184.4 g x 0.92 = 169.6 g = 5.98 oz lye.
Lye (NaOH) amount is calculated using each oil's SAP value multiplied by the oil weight, minus the superfat percentage. For a typical 32 oz batch with 60% olive oil and 40% coconut oil at 5% superfat, you need about 4.3 oz (122 g) of lye. The goat milk replaces water at a 2.5:1 ratio to lye.
| Oil | SAP Value | Hardness | Conditioning |
|---|---|---|---|
| Olive Oil | 0.1340 | 17 | 82 |
| Coconut Oil | 0.1787 | 79 | 10 |
| Lard | 0.1380 | 43 | 47 |
| Tallow | 0.1405 | 44 | 44 |
Use frozen goat milk to replace all the water in a cold-process recipe. The standard ratio is 2.5 ounces of milk per ounce of lye. For 4.3 oz of lye, you need about 10.8 oz (1.35 cups) of goat milk. Always freeze the milk into cubes and add lye slowly to prevent scorching.
The best goat milk soap uses a blend of oils for balanced properties. A classic recipe is 60% olive oil (conditioning), 25% coconut oil (cleansing/hardness), and 15% shea butter (luxury feel). Pure olive oil soap (Castille) is gentlest but takes 6–12 months to fully cure.
A typical 32 oz oil batch produces 7–8 bars at a material cost of $0.80–$1.50 per bar. The main costs are oils ($0.25/oz avg), lye ($0.15/oz), and goat milk ($1/cup). Compared to artisan goat milk soap at $6–$12/bar, homemade saves 80–90% on materials.
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Last Updated: May 2, 2026
This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.