Tinseth model
IBU Calculator
Estimate your beer's bitterness in International Bitterness Units from your hop schedule.
How IBU is calculated
IBU (International Bitterness Units) measures the isomerized alpha acids from your hops. The Tinseth modelmultiplies each addition's alpha-acid concentration by a utilization factor that rises with boil time and falls with wort gravity. Enter your hops below — the calculator sums every addition.
Hop additions
Estimated bitterness
29.3 IBU
- Addition 1 · 23.1% util
- 20.7 IBU
- Addition 2 · 11.4% util
- 8.6 IBU
Typical IBU by beer style
Target ranges to aim for, alongside each style's ABV.
| Beer style | Typical ABV | Typical IBU |
|---|---|---|
| American Light Lager | 2.8–4.2% | 8–12 |
| American Pale Ale (APA) | 4.5–6.2% | 30–50 |
| American IPA | 5.5–7.5% | 40–70 |
| Double / Imperial IPA | 7.5–10% | 60–120 |
| Stout (Dry Irish) | 4.0–4.5% | 25–45 |
| Imperial Stout | 8–12% | 50–90 |
| Hefeweizen | 4.3–5.6% | 8–15 |
| Saison | 5–7% | 20–35 |
| Belgian Tripel | 7.5–9.5% | 20–40 |
| Barleywine | 8–12% | 35–70 |
Frequently asked questions
How do you calculate ABV?+
The standard formula is ABV = (OG − FG) × 131.25, where OG is your original gravity (before fermentation) and FG is your final gravity (after). For example, an OG of 1.050 and FG of 1.010 gives (1.050 − 1.010) × 131.25 = 5.25% ABV. Enter your two gravity readings above and the calculator does it instantly, plus ABW, attenuation, and calories.
What's the difference between the standard and alternate ABV formula?+
The standard formula (× 131.25) is simple and accurate up to about 6–7% ABV. Above that it slightly under-reads, so the alternate formula — ABV = (76.08 × (OG − FG) / (1.775 − OG)) × (FG / 0.794) — is more accurate for strong beers and wines. Both are offered here; use the alternate for high-gravity brews.
What is apparent attenuation?+
Apparent attenuation is the percentage of sugars the yeast fermented, measured with a hydrometer: (OG − FG) ÷ (OG − 1) × 100. A typical ale finishes around 75%; a highly attenuative yeast or a simple-sugar recipe can exceed 80%. It's 'apparent' because alcohol is lighter than water, so the hydrometer reads a bit low.
What is ABW and how does it relate to ABV?+
ABW is alcohol by weight, versus ABV which is by volume. Because alcohol is less dense than water, ABW is about 0.79 × ABV — so a 5% ABV beer is roughly 4% ABW. US brewers label ABV; a few older or international measures use ABW.
How do I use the IBU and priming sugar calculators?+
The IBU calculator estimates bitterness from your hop additions (alpha acid %, weight, and boil time) using the Tinseth model. The priming sugar calculator tells you how much sugar to add at bottling to hit a target carbonation, based on your beer's temperature and volume. Both are linked from this page as part of the homebrew suite.
Are these brewing calculators accurate?+
They use the standard, widely-accepted homebrewing formulas (ABV, Tinseth IBU, temperature-based priming), so they're reliable planning tools. Real-world results vary with hydrometer calibration, temperature, yeast health, and hop freshness — always take a final hydrometer reading, and treat carbonation figures as a target to dial in.
Back to the ABV calculator or size your carbonation with the priming sugar calculator.
IBU is an estimate — actual bitterness varies with hop age, form, and hot-side losses.