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Brewhouse and mash efficiency calculator

Efficiency = measured gravity points × US gallons ÷ (pounds of grain × PPG). 5 kg of grain at 37 PPG that gives 25 L at 1.044 has recovered about 71% of its potential.

BrewMyBeer Editorial Team · 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, and your last inputs are remembered here.

Total mashed grain.

Weighted average points per pound per US gallon from your supplier’s data.

Pre-boil kettle volume for mash efficiency; fermenter volume for brewhouse efficiency.

Temperature-corrected reading of a well-mixed sample at the same stage as the volume.

Measured points against potential points

Potential points are each grain’s PPG multiplied by its weight in pounds, added up. Measured points are the gravity points of your wort multiplied by its volume in US gallons. BeerSmith defines efficiency as measured points divided by potential points.

For a mixed grain bill, enter a weighted average PPG: multiply each grain’s weight by its PPG, add the products and divide by the total weight.

Mash or brewhouse: choose the stage

BeerSmith describes brewhouse efficiency as the share of potential measured across the whole system into the fermenter. Use fermenter volume and original gravity for that number. Use pre-boil kettle volume and gravity for mash efficiency, which excludes boil and transfer losses.

Keep both readings from the same stage, correct the gravity for temperature, and leave out any sugar or extract added to the kettle, because it was never in the grain’s potential.

Before you use the result

  • Volume and gravity must come from the same stage.
  • A result above 100% means an input is wrong, usually PPG or volume.
  • For adults of legal drinking age. This tool describes a drink or batch, not its effect on a person.

A quick learning check

Why is brewhouse efficiency usually lower than mash efficiency on the same brew day?

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.