Lye Solution Calculator
Turn a lye weight into a solution: specify a lye concentration or a water:lye ratio and get the water needed, total solution weight and the resulting concentration. Calculates in your browser.
Water needed
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Show the math
A lye solution is just lye dissolved in water. From a ratio, water is a multiple of lye; from a concentration, water is whatever makes the lye that share of the total:
water = lye × ratio
water = lye ÷ (concentration ÷ 100) − lye
Always add lye to water slowly, never water to lye, the reverse can erupt. The solution gets very hot and gives off fumes; mix in a ventilated space with goggles and gloves. Stronger (more concentrated) solutions speed trace but leave less room for error.
What this does
A lye solution calculator turns a lye weight into a solution: specify a concentration or water:lye ratio and get the water, total weight, and resulting concentration.
How to use it
- Enter the lye weight.
- Choose concentration or water:lye ratio.
- Enter the value.
- Read the water and total solution.
How it works
A 33% concentration is roughly a 2:1 water:lye ratio and a common beginner-safe choice. Lower water speeds trace but leaves less margin for error.
water = lye ÷ (concentration ÷ 100) − lye
Understanding your result
A 33 percent concentration, roughly a 2 to 1 water-to-lye ratio, is a forgiving default for beginners. Using less water (a higher concentration) speeds trace and hardens the bar faster but leaves a thinner margin if you work slowly, so match the concentration to your pace and recipe rather than always chasing the fastest set.
Example
100 g of lye at 33% concentration needs about 203 g of water.
Sources & methodology
Last updated .
Frequently asked questions
Concentration or water:lye ratio — which should I use?
Either works. A 33% lye concentration is roughly a 2:1 water:lye ratio and a common beginner-safe choice; the tool converts between them.
What does a stronger solution do?
A more concentrated (lower-water) solution speeds up trace and cure but leaves less margin for error. More water gives you more working time.
How is the water found?
From a ratio, water = lye × ratio. From a concentration, water = lye ÷ (concentration ÷ 100) − lye.
Do you keep my numbers?
No — all calculations run locally in your browser.
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