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Maintained by an independent editor · Data reviewed 21 September 2026 · How we check the numbers

Almost every gelatin problem a home cook runs into comes down to one thing: the recipe was written for a gelatin that is not the gelatin you have. A French pastry book assumes sheets of a particular grade. An American recipe assumes a supermarket powder. Neither one tells you what to do when you are holding the other, and consumer packaging almost never prints the number that would let you work it out for yourself.

These pages exist to close that gap. They are written to be read standing in a kitchen rather than studied — short, specific, and honest about which figures are firmly established and which are reasonable estimates. Start with whichever question below is actually yours.

Understanding bloom strength

Bloom strength is the number that makes gelatin substitutable. If you only read one thing on this site before using the calculator, make it one of these two pages. They cover the same concept from different angles: the first is the more technical explanation, the second is organised around what you are actually trying to make.

What Is Gelatin Bloom Strength?

Answers the question "what does this number on a professional recipe actually mean, and why does it change how much gelatin I need?" It defines the Bloom test itself, lays out the sheet grade scale from bronze through platinum in a table giving the bloom range, relative set strength and typical uses of each grade, and then explains why two gelatins of the same weight do not set the same way. It also addresses Knox and generic supermarket powder specifically, and why consumer packaging leaves the value off. Read this one if you want to understand the mechanism rather than just get a number.

Sheets, powder, and converting between them

Sheets and powder are the same ingredient sold in two shapes, and the difference between them causes more failed sets than any other single factor. These two pages cover the comparison and the conversion.

Gelatin Sheets vs Powder: What's the Difference?

For anyone deciding which format to buy, or trying to work out why a recipe insists on one. A side-by-side table compares the two on how each is measured, the bloom grades each is sold in, how each is dissolved, clarity and flavour in the finished dish, and which cooking traditions favour which. The page then explains what happens when a recipe written for one format is cooked with the other. It is the right starting point if you have inherited a recipe that calls for sheets and have only ever used Knox, or the reverse.

Gelatin Sheets to Powder Conversion

The one page here with a working tool on it. Enter a sheet grade and a number of sheets and it returns the equivalent weight of powder; a toggle runs the same conversion in reverse, from a weight of powder to a count of sheets. The prose around the converter explains why there is no single sheet-to-powder rule that holds — grades differ in both bloom strength and sheet weight, and ignoring either one throws the result off. Worked scenarios cover the grade and quantity combinations that come up most often. Use this when you have a recipe in sheets and a jar of powder.

Getting the quantity right

How Much Gelatin Per Cup of Liquid?

For the situation where you have no recipe at all, only a liquid and an idea of the texture you want. A table gives quantities per cup for four target textures, from a soft set through to very firm, in both powder and sheets. The rest of the page is about what moves those numbers: acidity, sugar load, dairy, and the proteolytic enzymes in fresh pineapple and papaya that will stop a set from happening at all. A closing section deals with temperature, which is the other half of the same problem.

Not sure what bloom strength your gelatin is?

The main calculator starts with a diagnostic step — answer a few questions about your gelatin and it identifies the likely bloom value before running the conversion.

Go to the calculator →