Jam Sugar Ratio Calculator

Work out jam sugar ratio instantly with clear inputs, formula shown and shareable results.

About Jam Sugar Ratio Calculator

Sugar is set per kilogram of prepared fruit, and yield is roughly 75% of the combined weight after boiling off water; finished jam needs about 65 Brix to set and keep. Sugar is the preservative as well as the sweetener, so cutting the ratio below about 0.6 kg per kg of fruit gives a jam that must be refrigerated and eaten quickly.

Formulas

Sugar quantity

sugar kg = fruit kg x sugar per kg of fruit

Yield

yield kg = (fruit + sugar) x 0.75 after evaporation

Worked example

With the default values below, Jam Sugar Ratio Calculator returns Sugar needed of 1.500. Change any input above and every figure here is recalculated in your browser.

Inputs used

Prepared fruitminimum 0.1 kg: 2 kg
Sugar per kg of fruitminimum 0.1 kg: 0.75 kg
Jar sizeminimum 50 g: 340 g

Results

Sugar needed: 1.500 kg
Approximate jam yield: 2.625 kg
Jars filled: 7
Estimated finished sugar content: 57.9%

Step by step

1Values used
2Sugar quantity
3Yield
4Sugar needed= 1.500 kg
5Approximate jam yield= 2.625 kg
6Jars filled= 7
7Estimated finished sugar content= 57.9

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Jam Sugar Ratio figure worked out?

sugar kg = fruit kg x sugar per kg of fruit. Sugar is set per kilogram of prepared fruit, and yield is roughly 75% of the combined weight after boiling off water; finished jam needs about 65 Brix to set and keep.

Why does this matter?

Sugar is the preservative as well as the sweetener, so cutting the ratio below about 0.6 kg per kg of fruit gives a jam that must be refrigerated and eaten quickly.

What do I need to enter?

Enter prepared fruit, sugar per kg of fruit, jar size. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.