# Top-down Brew: Hop IBU Percentage Calculator

## Purpose: To calculate the IBUs and IBU percentages from multiple hop additions

Original gravity (in specific gravity or degrees Plato)
Target volume (gallons or liters)

Hop data: Name, weight, alpha acid percentage, boil minutes (with comma separated values):

Hop #1:
Hop #2:
Hop #3:
Hop #4:
Hop #5:
Hop #6:
US units (gallons, ounces) Metric units (liters, grams)
← Click here when the data entry is done.

## Results

*** Waiting for results ***

## Notes

This calculator can take the basic values from standard recipes (weight, time, alpha acid percentage) and easily convert these to IBU percentages for use in a flex recipe.

The IBU calculations are based upon the Tinseth formula. A small improvement upon the Tinseth formula is that aroma hops (defined as less than 2 minutes of boil) are assumed to have a utilization of 5%. The IBU calculations estimate boil volume and gravity for a 15% per hour boil off rate.

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This work is licensed under a Creative Commons Attribution 4.0 International License.