IBU Calculator (Tinseth)
Enter hop additions to estimate total IBU for your batch.
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How to Calculate IBU
International Bitterness Units (IBU) measure the bitterness in beer from hop alpha acids. The Tinseth formula is the most widely used method for estimating IBU in homebrewing.
Utilization increases with longer boil times (up to about 60–90 minutes) and decreases with higher wort gravity. A 60-minute addition at 1.050 gravity gives about 25% utilization.
IBU (International Bitterness Units) measures the concentration of iso-alpha acids from hops, measured in parts per million (ppm). The Tinseth formula used here: IBU = (oz × AA% × U × 74.89) / gallons, where U is hop utilization — a function of boil gravity and boil time.
Utilization increases with longer boil times (diminishing returns after 60 min) and decreases with higher wort gravity. A 60-minute addition at 1.040 gravity yields about 30% utilization; the same addition at 1.080 yields roughly 20%.
IBU style guidelines: lagers 8–15 IBU, American pale ales 30–50, IPAs 40–70, double IPAs 60–100+. Perceived bitterness depends on residual malt sweetness — a 40 IBU stout tastes less bitter than a 40 IBU lager because malt sweetness balances the bitterness.
Late hop additions (flameout, whirlpool, dry hop) contribute minimal IBU but add significant aroma. Most aroma compounds (myrcene, linalool, geraniol) volatilize during a long boil, so aroma hops should be added at or after flameout.
See also: ABV Calculator · Recipe Scaler