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Hop substitution calculator for bittering additions

Replacement weight = original weight × original alpha-acid percentage ÷ replacement alpha-acid percentage. Replacing 30 g of 6% hops with 9% hops gives 20 g as a starting estimate.

BrewMyBeer editorial · Sources checked 24 September 2026 · Calculated examples, not laboratory measurements. How we create content

Interactive tool

Calculate your batch

Change the example values. Inputs stay in your browser.

The bittering addition you are replacing.

Use the value on the original lot label.

Use the value on the replacement lot label.

Read the packet, not just the variety name

Alpha-acid percentage varies by lot. Enter the values printed on the two packets. The variety’s broad published range is a fallback for planning, not a substitute for the lot value when you have it.

This calculation preserves the mass of alpha acids added. Keep boil time, hop form and wort conditions comparable when using it for a bittering substitution. A change from whole cones to pellets or from a long boil to a whirlpool needs a fuller recipe model.

Separate bittering from aroma

An alpha-acid match does not recreate a hop’s aroma. For a late addition or dry hop, compare the desired sensory character and recipe purpose before deciding the weight. There is no universal alpha-acid equation for replacing citrus aroma with floral aroma.

Change one addition at a time and record the lot, quantity and timing. This makes the next batch more informative than replacing every hop and changing fermentation simultaneously.

Before you use the result

  • A stronger replacement generally needs less mass for the same alpha-acid charge.
  • Keep all hop weights in grams in this tool.
  • The result is not a prediction of measured IBU.

A quick learning check

Can 20 g of any 9% hop recreate the flavour of 30 g of a 6% hop?

Try a craft decision game →

Sources & further reading

These references explain the methods and limitations. The worked examples and learning questions on this page are BrewMyBeer calculations, not claims of hands-on testing.