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Check your all-grain mash efficiency against the 65-80% range, with gravity points worked out from measured SG, grain weight and PPG potential.

📘 How to Use

  1. Enter your total grain bill weight and the batch volume at the point you measured gravity
  2. Enter the measured specific gravity and set the grain potential (PPG)
  3. Read your mash efficiency, points achieved versus available, and the maximum possible gravity

Mash Efficiency Calculator

kg
L

Enter the volume at the point you measured gravity.

SG

Reading from a hydrometer or refractometer (e.g. 1.050).

37
25 46

Base malt is around 37. Adjust to match your grist.

science Results

Mash efficiency

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Points achieved

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points (lb·PPG)

Points available

—

points (lb·PPG)

Maximum possible gravity

—

SG at 100% efficiency

※ Efficiency = points achieved ÷ points available. Achieved = (SG−1)×1000×volume(gal); available = grain weight(lb)×PPG.

※ 65–80% is a typical homebrew guideline; it varies with equipment, crush and grist.

※ PPG is each malt's extract potential (base malt ≈ 37, sucrose ceiling 46). For mixed bills use a weighted average.

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Mash Efficiency Calculator | All-Grain Extraction from Grain Bill and SG

Work out your all-grain mash efficiency from a single gravity reading. Enter the grain bill, the volume you measured, the specific gravity and the grain potential, and see the percentage of sugar you actually pulled out of the grain, against the 65–80% range most brewers aim for. Inputs accept either kg/L or lb/gal.

💡 About this tool

Every all-grain brewer eventually asks the same question: of all the sugar locked up in the malt, how much did I actually get into the kettle? That number is your mash efficiency, and it is the single figure that decides whether your recipe hits its target gravity or lands short. Two brewers can use the identical grain bill and end up with very different beers purely because one crushes finer, sparges longer, or holds a steadier mash temperature.

This calculator works backwards from the reading you take with a hydrometer or refractometer. It compares the gravity points you actually achieved with the maximum your grain could theoretically give. The achieved points come from your measured gravity and the volume in the vessel; the available points come from the weight of grain multiplied by its potential (PPG). Divide one by the other and you have your efficiency. It also shows the maximum gravity that grain bill could ever reach at 100% extraction, so you can see how much headroom you have left and decide whether to chase a better crush or simply add a little more malt next time.

🧐 Frequently asked questions

Which volume should I enter? Use the volume in the vessel at the moment you took the gravity reading — usually pre-boil wort into the kettle. Mash efficiency is normally measured at that point, before boil-off concentrates the wort.

What PPG should I set? Base malts such as 2-row pale sit around 37 PPG. Wheat and Munich are close to that; crystal and roasted malts are lower. The reference ceiling is sucrose at 46 PPG, since one pound of pure sugar in one gallon gives 1.046. For a mixed grain bill, use a weighted average of your malts.

My result is over 100% — is that possible? No. Real extraction can never beat the theoretical maximum, so a figure above 100% means an input is off: a mistyped gravity, the wrong volume, or a PPG set too low. The tool flags this so you can recheck.

Why is anything below 60% flagged as below the typical range? Most all-grain setups land between 65% and 80%, and many homebrew references put the broad range at 60–80%. A reading below 60% often points to a coarse crush, a short or channeled sparge, or an off mash pH. It is a starting point for troubleshooting, not a verdict.

Does this account for boil-off or trub loss? No. It measures efficiency at the volume and gravity you enter. To compare brewhouse efficiency into the fermenter, enter the post-boil volume and gravity instead — the same math applies.

📚 Where the points system comes from

Brewers measure sugar with a borrowed yardstick: pure sucrose. Dissolve one pound of table sugar into one gallon of water and the specific gravity reads 1.046 — that is the origin of the "46 PPG" ceiling that every malt is rated against. A pale malt rated 37 PPG is simply saying it yields about 80% of what pure sugar would. The "points" themselves are just the decimals of specific gravity scaled up: a 1.050 wort is 50 points. Stack those two ideas together — points per gallon and pounds of grain — and the entire arithmetic of all-grain brewing falls out of two hydrometer readings and a kitchen scale.