About SoapCalcPro

Who Built This Site

My name is Dana Keller. I started making cold process soap in 2018 after burning through four different online lye calculators that either crashed, required sign-ups I didn't want, or gave me wildly different results for the same recipe. Out of frustration, I built my own spreadsheet. That spreadsheet eventually became SoapCalcPro.

In the six years since, I've made soap in everything from small test batches to 20-pound production runs. I sell at farmers markets in the Pacific Northwest under my own small-batch label, and I teach cold process soap making workshops locally a few times a year. I also started making soy candles around 2020 — which is why this site expanded to include candle-specific tools like the burn time calculator and fragrance load estimator.

I don't have a chemistry degree. What I have is six years of hands-on experience, a lot of failed batches that taught me something, and a genuine frustration with tools that are either too complicated for beginners or too oversimplified to be useful for anyone making more than a hobby batch. SoapCalcPro tries to sit in the middle.

What This Site Covers

SoapCalcPro provides free calculators and guides for home soap makers and small-batch producers:

• Lye Calculator — NaOH amounts for cold process bar soap, with adjustable superfat percentage
• Fragrance Calculator — fragrance oil amounts by PPO (per pound of oil), with scent load guidance
• Batch Scaler — scale any recipe up or down while preserving oil ratios and superfat
• Cost Calculator — ingredient cost per bar or per ounce, including packaging
• Burn Time Calculator — estimated candle burn time based on wax weight and wick size

The guides section covers the topics I get asked about most at workshops: lye safety, the best oils for different bar types, how to troubleshoot common soap problems, and the science behind superfat and saponification.

How I Test and Update the Calculators

Every calculator on this site reflects real formulas I use in my own making. The lye calculator uses published SAP (saponification) values from established soap making references, including values I've personally verified by cross-referencing against multiple sources. I update SAP values if I find corrections in the peer-reviewed literature or when ingredient suppliers publish updated specifications.

The burn time calculator is based on burn rates I've tested across four different wax types over multiple sessions, combined with burn rate data from candle wax suppliers. It's an estimate — real burn time depends on wick centering, fragrance load, ambient temperature, and how well the candle was cured. I note these variables in the guide.

I make new batches regularly and use this site as my own tool. That means I catch errors in my own making, not in theory.

Safety Note

Working with lye (sodium hydroxide) is inherently hazardous and requires proper protective equipment and technique. The calculators and guides on this site include safety guidance, but they are not a substitute for thorough research before your first batch. Read the full lye safety guide, watch multiple tutorials, and never work with lye unsupervised until you're confident with the process. Neither this site nor its author is responsible for injury resulting from the use of these tools.

Get in Touch

Questions about a recipe, a calculator result that doesn't look right, or a guide topic you'd like to see covered — use the contact form. I check messages regularly and genuinely enjoy hearing from other makers.