IBU calculator

Estimate your beer's bitterness with the Tinseth formula: batch volume, boil gravity and up to three hop additions.

Bitterness

Batch volume (litres) Boil gravity

Hops (g)Alpha acids (%)Boil time (min)

Bitterness (IBU, Tinseth)—

Weight, alpha acids and boil time for each addition. Leave a row empty to ignore it. Whirlpool and dry hops add little or no IBU in this formula.

How the Tinseth formula works

Each addition contributes IBU = utilization × alpha acids × weight / volume. Utilization grows with boil time and falls as gravity rises: 1.65 × 0.000125^(gravity − 1) × (1 − e^(−0.04 × minutes)) / 4.15. A 60-minute addition in 1.050 wort reaches about 23 % utilization.

Questions

Why does my software give a different IBU?

IBU formulas differ (Tinseth, Rager, Garetz) and so do assumptions on whirlpool and pellet hops. Mashwerk lets you pick the formula and matches BeerSmith's calculations.

Do whirlpool hops add bitterness?

Some, depending on temperature and time. Mashwerk models whirlpool additions; this quick calculator only counts the boil.

What is a balanced IBU?

Compare IBU to gravity: an IBU/OG ratio around 0.5 (for example 25 IBU at 1.050) tastes balanced; a best bitter sits around 0.7, IPAs often around 1.

Track every batch, not just one number

Mashwerk computes this for every recipe and brew, from your own equipment and readings. Free plan, no credit card.

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