IBU Calculator
Calculate the bitterness (IBUs) of your homebrew. Enter your batch volumes, wort gravity, and up to 6 hop additions.
Estimate beer bitterness from hop additions
Use the IBU calculator to estimate bitterness from boil volume, final volume, wort gravity, hop alpha acid, hop weight, and boil time.
Example IBU planning
Enter your boil volume, final volume, and original gravity, then add each hop addition with alpha acid, weight, and minutes in the boil. Longer boil additions generally contribute more bitterness than late additions.
- Enter boil volume, final volume, and original gravity.
- Add each kettle hop with alpha acid, weight, and boil time.
- Compare the result with your recipe target and adjust bittering hops first.
Watch for: Use the alpha acid printed on your hop package when it differs from the preset value.
Frequently asked questions
What does IBU measure?
IBU estimates dissolved bitterness compounds in beer, mainly from isomerized hop alpha acids.
Why do boil time and gravity matter?
Longer boil times increase utilization, while wort gravity affects how efficiently alpha acids are isomerized and dissolved.
Should I use the hop selector or manual alpha acid?
Use the hop selector as a shortcut, but enter the alpha acid from your hop package when you have it.
Can dry hops be included?
Dry hops add aroma and flavor but little calculated boil bitterness, so this calculator focuses on kettle additions.
CaptainBrew
Create recipes, compare brewing tools, and explore a huge library of homebrew knowledge in one place.