All-Grain Recipe Calculator
Calculate grain weight and water volumes for all-grain brewing based on batch size, target gravity, and mash efficiency.
About this calculator
All-grain brewing extracts sugar from crushed malt during the mash, and how much grain that takes depends on three things that all pull equally hard on Grain Weight: Batch Size, Target OG Points, and Mash Efficiency each move the required grain bill by roughly the same proportion for an equivalent percentage change -- doubling your batch size and doubling your target gravity both roughly double the grain needed, and halving your mash efficiency roughly doubles it too, since Grain Weight is directly proportional to the total gravity points you need and inversely proportional to how efficiently your system extracts them. Primary Grain Type sets the points-per-pound-per-gallon (PPG) potential the calculation assumes -- 2-Row at 37 PPG is the workhorse base malt for most styles, Pilsner runs slightly lower at 36 PPG, and Wheat malt slightly higher at 38 PPG, though real maltster lab analyses vary by a point or two from these textbook figures depending on the specific malt and lot. Total Water Needed splits into Mash Water (roughly 1.33 quarts per pound of grain, enough to keep the mash from running dry) and Sparge Water (whatever additional water brings the kettle up to pre-boil volume, accounting for grain absorption of roughly 0.125 gallons per pound).
Target OG is reported as a direct decimal conversion of Target OG Points and does not respond to Batch Size, Mash Efficiency, or grain type at all -- it's simply what you told the calculator you're aiming for, restated in standard hydrometer notation. This calculator does not account for late extract additions, mash thickness beyond the assumed 1.33 qt/lb ratio, or strike water temperature -- pair it with a strike water calculator for the full mash setup.
Inputs
Results
Grain Weight
9.38 lbs
≈ 2 bags of sugar
Total Water Needed
7.17 gallons
≈ 7 milk jugs
How to Use This Calculator
- Enter your target batch size in gallons and target OG points.
- Set mash efficiency (%) — typically 70–80% for most systems.
- Select your primary grain type (2-Row, Pilsner, or Wheat).
- Review Grain Weight, Total Water Needed, Mash Water, Sparge Water, and Target OG.
How the result changes with Mash Efficiency
| Mash Efficiency | Grain Weight | Total Water Needed |
|---|---|---|
| 50 | 13.51 lbs | 7.69 gallons |
| 54 | 12.51 lbs | 7.56 gallons |
| 95 | 7.11 lbs | 6.89 gallons |
What each input means
- Batch Size
- Final volume of beer into the fermenter in gallons. Typical homebrew batch is 5 gallons.
- Target OG Points
- Target original gravity in points (e.g., 50 means OG 1.050). A pale ale is typically 45-55.
- Mash Efficiency
- Expected brewhouse efficiency. New brewers typically see 65-72%, experienced brewers 75-85%.
- Primary Grain Type
- Base malt type, which sets the points-per-pound-per-gallon (PPG) used to size the grain bill.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersBatch Size = 5, Target OG Points = 50, Mash Efficiency = 72, Primary Grain Type = 1 = 4 input(s) provided
- Calculate Grain WeightGrain Weight9.38 = 9.38
- Calculate Total Water NeededTotal Water Needed7.17 = 7.17
- Calculate Mash WaterMash Water3.12 = 3.12
- Calculate Sparge WaterSparge Water4.05 = 4.05
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does mash efficiency affect the grain bill as much as batch size does?
Grain Weight is calculated as total gravity points needed divided by your malt's potential times your efficiency -- so a percentage change in Mash Efficiency changes the denominator by roughly that same percentage, exactly mirroring what a percentage change in Batch Size or Target OG Points does to the numerator. A brewer moving from 65% to 75% efficiency (a common new-brewer-to-experienced-brewer jump) needs meaningfully less grain for the same beer, which is one of the biggest cost levers in scaling up a homebrew system.
Why doesn't Target OG change when I adjust batch size or efficiency?
Target OG is just Target OG Points converted into standard hydrometer decimal notation (so 50 points displays as 1.050) -- it's a direct restatement of the number you entered, not a computed outcome of the recipe. Batch Size, Mash Efficiency, and Primary Grain Type all affect how much grain and water it TAKES to reach that target gravity, but none of them change what the target itself is.
How much does grain type actually matter compared to batch size or efficiency?
Less than you might expect -- the PPG spread between 2-Row, Pilsner, and Wheat base malts in this calculator is only 36 to 38, a difference of about 5%, while Batch Size, Target OG Points, and Mash Efficiency can each easily swing by 20% or more between typical recipes and brew days. Grain type selection matters more for flavor and beer style than for how much grain you need to buy.
Why is sparge water sometimes zero in the results?
Sparge Water is floored at zero rather than allowed to go negative, which happens when Mash Water alone already exceeds your pre-boil volume target -- typically with a large grain bill (high Target OG Points or Batch Size) at a thick mash ratio. In that case you're effectively doing a full-volume mash with no separate sparge step, and Total Water Needed equals Mash Water alone.
Should I trust the PPG values for grain types not close to my actual malt?
Use them as reasonable starting estimates, not exact figures -- 37/36/38 PPG for 2-Row, Pilsner, and Wheat are textbook averages, but a specific maltster's lab analysis sheet for your actual grain lot can run a point or two higher or lower. For a dialed-in recipe, check your grain supplier's published extract potential and adjust Mash Efficiency to compensate if your malt's real PPG differs from what this calculator assumes.
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