Brewing calculators
Free online calculators for homebrewing. Instant ABV, bitterness, carbonation and other parameters.
ABV calculator
Calculate alcohol by volume from original and final wort gravity. The formula works for most beer styles.
IBU calculator
Bitterness estimate by the Tinseth method. Accounts for hop alpha acid, mass, boil time and batch volume.
Carbonation calculator
Calculate primer (dextrose or sugar) to hit the target CO₂ level in bottles.
Dilution calculator
Calculate how much water to add to drop gravity or ABV to the target.
Brewer's reference
Short notes on each calculator — so you know what you are actually computing.
What is ABV?
ABV (Alcohol By Volume) is the alcohol fraction of the beer. The main strength number. It is computed from the difference between original (OG) and final (FG) gravity: yeast eat sugar, gravity drops, alcohol rises.
Typical range: lager 4–5%, IPA 5–7%, imperial stout 8–12%.
What is IBU?
IBU (International Bitterness Units) measures beer bitterness. It depends on hop alpha acid, amount, boil time and wort volume. Bitterness isomerizes during the boil — longer boil, more IBU.
Typical range: lager 15–25, IPA 40–70, imperial IPA 60–100+.
Carbonation and primer
Carbonation is dissolving CO₂ before packaging. Primer (dextrose, sugar) goes into the bottles: leftover yeast eat it and release CO₂. Level depends on style: lager — 2.2–2.5 vol., wheat — 3.5–4.0 vol.
Dilution
Dilution is adding water to lower gravity or ABV. Used when wort came out too concentrated, or when adjusting after fermentation. The formula balances extract before and after.
More calculators — in the app
On the site: ABV, IBU, carbonation and dilution. In the app — color, hydrometer, refractometer, water, priming and yeast pitch. Offline.