Online Tool Store
Beer Recipe Calculator
Calculate original gravity, IBU bitterness, colour, and expected ABV for a homebrew recipe from grain bill, hops, and batch size.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Fun & Misc
Beer Recipe Calculator
Frontend preview — no upload or external service.
Recipe figures
20 L at 72% efficiency: OG about 1.048, IBU about 28, colour around 8 EBC. Fermenting to 1.010 gives roughly 5.0% ABV.
How the Beer Recipe Calculator works
- Enter batch size and your measured mash efficiency — using a default rather than your own number is the main source of error.
- Add the grain bill and the hop additions with their alpha acid and boil times.
- Compare the calculated figures against the style you are aiming at, then measure actual gravity rather than trusting the calculation.
The method
Original gravity comes from fermentable extract, batch size and efficiency; ABV comes from the drop between original and final gravity.
ABV ≈ (OG − FG) × 131.25
A drop from 1.048 to 1.010 is 0.038, giving about 5.0% ABV. Bitterness depends on alpha acid, quantity, boil time and gravity, since utilisation falls in a denser wort.
FAQ
Why does my efficiency differ from the recipe's?
Because it depends on your crush, mash schedule, water volumes and equipment. Efficiency is a property of your system, not of the recipe, and using someone else's figure produces the wrong gravity every time.
Why do late hop additions add so little bitterness?
Because isomerisation of alpha acids takes time at boiling temperature. A 60-minute addition contributes most of the bitterness; a flameout addition contributes aroma and very little IBU.
How accurate is calculated ABV?
Close enough for a homebrew, using a standard formula on hydrometer readings. Precise measurement needs temperature correction and, for high-gravity beers, a more elaborate formula than the simple multiplier.
How we compare
| Feature | Online Tool Store | Doing it by hand | A single-purpose app |
|---|---|---|---|
| Uses your own efficiency | ✓ | Recipe default | Yes |
| IBU with utilisation | ✓ | Simplified | ✓ |
| No brewing software | ✓ | ✓ | ✗ |
| Nothing stored | ✓ | ✓ | ✗ |
Beer Recipe Calculator uses your measured efficiency, since borrowing someone else's is what makes a well-followed recipe miss its gravity.