United KingdomTier 2
Brewhouse efficiency calculator
Grain bill and measured OG in. Your brewhouse efficiency percentage out.
Free·No sign-up·Last checked 2026-08-27
Formula
Max points = grain_kg × potential (L°/kg)
Actual points = (OG − 1) × 1000 × batch_L
Efficiency% = actual points ÷ max points × 100
Worked example. 4.5 kg grain at 308 L°/kg potential, 19 L batch, OG 1.050 → 950 actual points ÷ 1386 max points = 68.5%.
Method
Litre-degrees per kilogram (L°/kg) — the metric malt-extract unit
L°/kg is the metric equivalent of the American "points per pound per gallon" figure, converted using the exact litre/gallon and kilogram/pound ratios (1 ppg ≈ 8.345 L°/kg). UK and European maltster spec sheets often quote extract potential this way directly.
Questions
Most home all-grain setups land between 65% and 80%. Below 60% usually points to a crush that's too coarse or a stuck/channeled sparge; above 85% is unusual outside commercial-scale equipment.
308 litre-degrees per kilogram (equivalent to about 37 points per pound per gallon) is a common average for base malt. Specialty and crystal malts run lower; check your maltster's spec sheet for an exact figure if you want a more precise number.