Coffee Brew Ratio Calculator
Brew method + cups → recommended coffee grams and water ml, with SCA Golden Cup ratios.
Result
How to use this calculator
- Pick a brew method.
- Set how many servings and the serving size in ml (~240 ml mug, 150 ml SCA cup).
- Read the coffee weight and water volume to use.
About this calculator
Coffee brewing is a controlled extraction: a fixed coffee-to-water ratio (by weight) yields a consistent strength. The Specialty Coffee Association's "Golden Cup Standard" anchors at 1:17 (55-60 g per litre) for drip brewing, while immersion methods (French press, cold brew) run lower because total contact time is longer and grind is coarser. Ratios are by weight — measuring coffee in tablespoons works but is much less consistent because density varies with grind and bean type.
What this calculator does
This calculator returns the coffee weight (in grams) and water volume (in ml) needed for a given brew method and serving count, plus brewing temperature and time guidance. Ratios are by weight, anchored to the Specialty Coffee Association's Golden Cup Standard for drip and to practitioner consensus for the other methods (French press 1:15, AeroPress 1:13, cold brew concentrate 1:8, moka pot 1:10, siphon 1:16).
How it works — the formula
water_ml = servings × serving_ml
coffee_g = water_ml / ratioA coffee-to-water ratio of 1:R means 1 gram of coffee per R grams (or ml) of water. Since 1 ml of water ≈ 1 g at brewing temperatures, the calculation works equivalently in ml. SCA's Golden Cup Standard specifies 55-60 g coffee per 1 L water (1:16.7-1:18.2) as the ratio band that yields the ideal extraction yield (18-22%) and total dissolved solids (1.15-1.35%).
Worked examples
- Inputs:
- method=drip, cups=1, cup=250 ml
- Output:
- 14.7 g coffee + 250 ml water; 1:17 ratio
Standard SCA Golden Cup for a single mug.
- Inputs:
- method=french-press, cups=2, cup=250 ml
- Output:
- 33.3 g coffee + 500 ml water; 1:15 ratio
Use coarse grind; steep 4 minutes.
- Inputs:
- method=cold-brew, cups=4, cup=250 ml
- Output:
- 125 g coffee + 1000 ml water; 1:8 ratio
Steep 12-18 hours; the result is concentrate to be diluted 1:1 in the glass.
When to use this vs other tools
Use this for non-espresso brew methods. For espresso, the dedicated tool is calibrated for the 1:2 dose-to-yield regime.
- Espresso Ratio
Use for espresso — high-pressure, fine-grind brewing with different ratio conventions (1:1.5 to 1:3).
- Tea Brewing
Use for tea — a parallel water-temperature + steep-time guide for the second-most-common hot drink.
- Recipe Scaler
Use to scale a known recipe up or down — ratios are invariant.
Authority note
SCA is the international professional body for specialty coffee. The Golden Cup Standard is the canonical reference for drip brewing; immersion-method ratios used here are practitioner consensus from Scott Rao and James Hoffmann.
Limitations
- Ratios assume medium roast and medium grind appropriate to each method. Lighter / darker roasts may benefit from ratio adjustments.
- Doesn't account for water mineral content (calcium, magnesium, bicarbonate) which strongly affects extraction.
- Method ranges are central values, not strict rules — taste-adjust by ±10%.
- Excludes pre-infusion / bloom water (typically 2× coffee weight, ~30 s) which is folded into the total water count.
Brewing variables (water temperature, grind, time, mineral content) interact. Use the ratio as a starting point and tune to taste.
Frequently asked
Why weigh coffee instead of scooping?+
What is the Golden Cup Standard?+
Cold brew ratio so different — why?+
Espresso?+
Does grind size matter?+
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