Change any value below and click Calculate and the BUs will be calculated. If you want to make multiple additions, simply fill in another line’s Alpha Acid Percentage, Mass Added, and Time Boiled fields. The Utilization Percentage, Bittering Units, and Total Bittering Units fields are calculated for you; any entries you make to those fields are ignored.
The Bitterness Calculator takes into account both the time of boil and the wort gravity during the boil. The numbers have been developed by Glenn Tinseth, based partly on data and partly on experience. Your experience and brewing practices may be different so here’s the official disclaimer: Your Mileage May Vary (YMMV).