IBU Bitterness Calculator

Summary

Add hop additions with weight, alpha acid, and boil time to calculate total IBU using the Tinseth or Rager formula.

How it works

1. Enter your batch size and pre-boil original gravity.
2. Choose a formula: Tinseth (most common) or Rager.
3. Add each hop addition: weight in grams or ounces, alpha acid percentage, and boil time.
4. The calculator updates the IBU contribution of each addition in real time.
5. Total IBU is summed across all additions and displayed with a bitterness style guide.

Use cases

• Plan the bitterness level of a homebrew IPA, pale ale, or lager before brewing.
• Compare how changing boil time or alpha acid affects overall IBU.
• Verify a recipe from a book that uses a different formula than your brewing software.
• Scale a recipe up or down and recalculate the exact hop quantities needed.
• Dial in late hop additions versus bittering additions for balance.
• Cross-check IBU between Tinseth and Rager to understand formula variation.

Frequently Asked Questions