Recipes, batches and cost per bar — one app, pay once.

BatchBench is an offline workbook for hobbyist and small-batch soap and candle makers: calculate lye and wax, log every batch, know when it has cured, and see what each bar or jar really costs. No account, no subscription.

Free: calculators plus 5 recipes and 10 batches. Pro (one-time): unlimited, stock and cost, PDF batch sheets, CSV, backup, no ads. Android, iOS and Windows — store links coming soon.

Safety: lye (sodium/potassium hydroxide) causes chemical burns. Wear gloves and eye protection, add lye to water (never water to lye), and always verify the lye weight with a second calculator before making soap. Results below are estimates from typical SAP values; oils vary by supplier.

Free soap lye calculator

Lye

Superfat %

Water % of oils

SAP values: SoapCalc.net cross-checked with Soaply.net. Oils not listed here are in the app (149 oils).

Candle wax & fragrance calculator

Vessel (ml)

Fill %

Wax density g/ml

Fragrance load %

Jars

Fragrance load is % of wax weight. Check your wax supplier's maximum; density varies by wax — calibrate with a test pour.

Price to charge

Cost per unit

Margin %

Marketplace/card fee %

Fixed fee per sale

Why BatchBench

One-time price instead of a yearly subscription.
Soap and candles in one workbook, with a batch log and cure timer.
Lye math checked against an independent reference implementation.
Works offline; your recipes stay on your device.

FAQ

Does it work offline? Yes, everything is stored on your device.
Windows notifications? Cure reminders are OS notifications on Android/iOS; on Windows batches are marked ready when you open the app.
Is the lye result guaranteed? No calculator is. Verify with a second one and follow safe soapmaking practice.

How the lye calculation works · Fragrance load explained · Pricing handmade soap