IBU Calculator

Estimate beer bitterness from hop additions with Tinseth, Rager, Garetz or Noonan, including hop stands.

IBU formula

Batch size

Post-boil kettle volume

Hot wort left in the kettle at flameout — 4% cooling shrinkage is applied automatically.

Pre-boil gravity

Post-boil gravity

Gravity at the end of the boil — used for hop-stand additions.

Boil time

min

First wort and mash hops steep for the full boil.

Fermenter top-up

Water added in the fermenter dilutes bitterness. Leave empty for none.

Hop additions

Addition 1

Amount

Alpha acid

Time

min

Use

Form

Total bitterness (IBU)

47.7

Want this running live inside your recipes?

Brewfather recalculates your whole recipe as you type — gravity, IBU, color, water and more. Free to start.

How this calculator works

IBU estimates bitterness from hop amount, alpha acid, contact time, wort strength, volume, hop use and optional hop-stand temperature.

The selected bitterness model changes the estimate, so compare recipes using the same model whenever possible.

Hop stand additions can still add bitterness, especially when the wort stays hot for a long time.

Use the alpha-acid percentage from the actual hop package, because storage and crop year matter.
If your beers consistently taste more or less bitter than predicted, adjust your equipment profile in Brewfather.