Soap Lye Calculator - Trace

Soap Lye Calculator - Trace

Batch Tracker & Cure Journal

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Free
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Released
May 7, 2026
Updated
October 17, 2026

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About

Calculate lye, log every batch, and keep your soap recipes in one place. Trace is a lye calculator, recipe book and batch log for cold process and hot process soapmakers. LYE CALCULATOR - NaOH or KOH amounts for your oil blend, by weight or by percentage - 33 oils with SAP values from SoapCalc's oil table, checked against Codex Alimentarius ranges - Superfat, water-to-lye ratio and KOH purity (100%, 95%, 90% or 85%) - Grams or ounces; decimal points or commas - Run every recipe through a second lye calculator before you make it BATCH LOG - Log each batch with its oils, lye, water, temperatures, trace and costs - Cure countdown with days remaining and a Ready badge - Weigh-ins to follow water loss during the cure - Rate each cured batch: pH, lather, conditioning, hardness and scent RECIPES - Save your own recipes and scale them to any batch size - Start a batch from a recipe with its oils filled in - Filter by testing, proven or production - 30 starter recipes to begin from SOAP PROPERTIES - Predicted hardness, cleansing, conditioning, bubbly and creamy lather - Iodine value and INS TRACE PRO - Unlimited recipes and batches - All 7 property predictions - All 30 starter recipes The free version includes the lye calculator, 5 saved recipes, 10 batches, hardness and cleansing predictions and 3 starter recipes. Lye is caustic. Wear goggles and gloves, add lye to water (never water to lye), and keep children and pets away. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
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What's New in Soap Lye Calculator

1.41

October 17, 2026

Correction: the coconut oil lye value was 4.4% too high (0.191 instead of 0.183 g NaOH per gram of oil), so recipes with coconut oil got more lye than intended. If you made a recipe with coconut oil at a superfat below about 5%, recheck it in this version and in a second lye calculator before using those bars. - Every oil's SAP value rechecked against SoapCalc and Codex Alimentarius; jojoba, beeswax, tamanu, cupuaçu, rice bran and others corrected - KOH purity setting for liquid soap (most KOH sold is 90%) - INS now uses the standard formula (it read about 60 points low) - Ounces in the calculator, recipes and batches when chosen in Profile; decimal commas accepted - Start a batch from a recipe with its oils filled in; recipes can be deleted - Lye safety notes next to every lye amount - Pro subscribers no longer see the paywall while the App Store is still answering

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Subscriptions & In-App Purchases

Trace Pro

Pro aboneligiyle Trace'in tam deneyimini yasayin.

$4.991 Month
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