Beer Priming Sugar Calculator
Bottle conditioning carbonates beer naturally: a measured dose of fermentable sugar at packaging is consumed by remaining yeast, producing CO2 that dissolves into the sealed bottle. Getting the dose right is the difference between flat beer, perfect carbonation, and dangerously over-pressurised bottles. This calculator estimates the CO2 already dissolved in your finished beer from its warmest temperature, subtracts it from your target carbonation level, and converts the difference to grams of priming sugar for your whole batch. Every empirical factor is a user-editable input so you can match your recipe and chosen sugar.
Priming sugar formula
Residual CO2 = 3.0378 - 0.050062 * T + 0.00026555 * T^2 (T in degrees F)
CO2 needed = target volumes - residual CO2
Sugar grams = CO2 needed * grams-per-volume-per-litre * litres
Sugar ounces = sugar grams / 28.3495
The residual CO2 equation is the widely used fit relating dissolved CO2 to the warmest temperature reached. Corn sugar (dextrose monohydrate) takes about 3.9785 grams per volume per litre; table sugar (sucrose) about 3.62. Set the grams-per-volume input to match your sugar.
Bottle conditioning context
- Confirm a stable final gravity over several days before priming; unfinished beer can over-pressurise bottles.
- Enter the warmest temperature the beer reached after fermentation, not its current cellar temperature.
- Typical CO2 targets: British ales 1.5 to 2.0, American ales 2.2 to 2.7, lagers 2.4 to 2.9, Belgian and wheat 3.0 and up.
- Dissolve priming sugar in boiled water and gently blend into the whole batch for even carbonation.
- Use bottles designed for carbonated beverages; reused commercial beer bottles are rated for these pressures.
Priming sugar: frequently asked questions
How is priming sugar weight calculated?
First the carbon dioxide already dissolved in the beer (residual CO2) is estimated from the highest temperature the beer reached. The CO2 you still need is the target volumes minus the residual volumes. Each volume of CO2 requires about 3.9785 grams of corn sugar (dextrose) per litre of beer, or about 4.13 grams of table sugar. Multiply by your batch volume to get total grams.
Why does beer temperature matter for priming?
Cold liquid holds more dissolved CO2 than warm liquid. The residual CO2 in finished beer depends on the warmest temperature it reached after fermentation, since that point set the lowest CO2 retention. Using a higher temperature gives a higher priming sugar dose, so always enter the warmest temperature the beer experienced to avoid over-carbonation.
How many CO2 volumes should I target?
One volume means the dissolved CO2 would occupy the same space as the beer at standard conditions. Typical targets are about 1.5 to 2.0 for British ales, 2.2 to 2.7 for American ales, 2.4 to 2.9 for lagers, and 3.0 or more for Belgian and wheat styles. These are user-editable; consult your recipe.
Can I use table sugar instead of corn sugar?
Yes. Table sugar (sucrose) is slightly more fermentable by weight than corn sugar (dextrose monohydrate), so you need roughly 0.91 times as much. This calculator lets you set the grams of sugar required per CO2 volume per litre, so you can enter the value for your chosen sugar.
Will the right priming dose guarantee safe bottles?
Priming math assumes fermentation is fully complete and gravity is stable. Adding sugar to beer that is not finished fermenting can over-pressurise and burst bottles. Always confirm a stable final gravity over several days before bottling, and use bottles rated for carbonation pressure.
Official sources
- U.S. Alcohol and Tobacco Tax and Trade Bureau: TTB beverage alcohol.
- UNSW School of Physics: Music acoustics (gas and solution physics references).
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.