Hop Utilisation IBU Calculator

Work out hop utilisation ibu instantly with clear inputs, formula shown and shareable results.

About Hop Utilisation IBU Calculator

Tinseth's model computes utilisation as the product of a bigness factor, which falls with wort gravity, and a time factor of (1 - e^(-0.04t))/4.15. IBU is then hop mass times alpha acid fraction times utilisation, scaled to volume. Utilisation peaks around 30% at long boil times in low-gravity wort.

Formulas

Tinseth utilisation

Utilisation = 1.65 x 0.000125^(SG-1) x (1 - e^(-0.04t)) / 4.15

IBU

IBU = hop mass (g) x alpha acid fraction x utilisation x 1000 / volume (L)

Worked example

With the default values below, Hop Utilisation IBU Calculator returns International Bitterness Units of 41.520. Change any input above and every figure here is recalculated in your browser.

Inputs used

Hop Additionminimum 0 g: 30 g
Alpha Acid Contentaccepts 0.01–30 %: 12 %
Boil Time For This Additionminimum 0 minutes: 60 minutes
Batch Volumeminimum 0 L: 20 L

Results

International Bitterness Units: 41.520
Hop Utilisation: 23.066%
Alpha Acid Units: 360.000
Boil Time Factor: 0.21910

Step by step

1Values used
2Tinseth utilisation
3IBU
4International Bitterness Units= 41.520
5Hop Utilisation= 23.066
6Alpha Acid Units= 360.000
7Boil Time Factor= 0.21910

Assumptions and limits

The result is derived only from the 4 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 5 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

Why does high gravity reduce utilisation?

Isomerised alpha acids are less soluble and are also adsorbed onto trub and yeast, both of which increase in dense wort. Strong beers need proportionally more hops for the same bitterness.

Do late and whirlpool additions contribute IBU?

Some, but far less. Below about 80 C isomerisation slows sharply, so whirlpool hops contribute aroma and modest bitterness that Tinseth's model does not capture well.