Glaze Batch Calculator
Turn a glaze recipe written in percent into exact grams for any batch size, and check that your recipe totals 100%.
| Ingredient | % | Grams | |
|---|---|---|---|
| 2000 g | |||
| 1725 g | |||
| 1275 g |
Additions like bentonite are usually specified as an extra 1 to 2% on top of the base 100%, not folded into it. Weigh the base ingredients to 100% first, then add the addition's grams separately using the same batch size.
Wear a NIOSH-rated dust mask when weighing dry glaze materials. Silica dust is the real long-term hazard in a home pottery studio, not any single chemical. Wet-clean spills and surfaces with a sponge instead of sweeping or blowing dust into the air.
How it works
Most glaze recipes are written as percentages that add up to about 100, which is convenient for scaling but not that convenient for weighing on a scale. This calculator converts each ingredient's percentage into grams for whatever batch size you're mixing, so a recipe written on a card or in a book turns directly into numbers you can weigh out. It also adds up your percentages so you can catch a typo or a missing ingredient before you've already weighed half the bucket.
Worked example: a 5000 g batch (roughly a five-quart bucket at typical glaze density) of a recipe that's 40% feldspar, 34.5% silica, and 25.5% kaolin. That comes out to 2000 g of feldspar and 1725 g of silica, and the three percentages add up to exactly 100, so the recipe checks out before you weigh anything. If the recipe also calls for 2% bentonite as a suspension aid, that's an addition on top of the 100%, worked out the same way against the same 5000 g batch size rather than folded into the base three ingredients.
FAQ
Why doesn't my recipe add up to exactly 100%?
Small rounding in a published recipe, or a missing line item, both show up as a total that's a little off from 100. Anything more than half a percent off is worth double-checking against the original source. Additions like bentonite, CMC gum, or a colorant are usually meant to sit on top of the 100% base rather than be part of it, so don't let those push your check total off.
What batch size should I mix?
A 5000 g batch is a common starting point since it fills a standard glaze bucket with room to stir, and it's large enough that small scale errors don't throw off the color or texture much. For a new recipe you haven't tested, mixing a small 500 g or 1000 g test batch first is worth the extra step before committing a full bucket of materials.
Do I need a precise gram scale?
Yes for anything beyond a rough test. A kitchen scale that reads to the gram is enough for most hobbyist batches; the finer jewelry-style scales matter more for small additions like colorants that are measured in single grams against a large batch.
Is it safe to just eyeball a glaze recipe?
Not for anything you plan to eat or drink from. Glaze chemistry depends on getting the ratios right, and food-safe results specifically depend on firing a tested recipe to the right cone, not on approximate measuring.
For more on mixing and applying glaze, see how pottery glaze works, brushing, dipping, and pouring glaze, and what beginners need to know about food-safe glaze.