Coffee Brewing Ratio Calculator
The coffee-to-water ratio is the single most important variable in brewing filter coffee consistently. Professional coffee organisations including the Specialty Coffee Association recommend measuring both coffee and water by weight in grams rather than by volume, because ground coffee density varies significantly with grind size and roast level. The SCA Golden Cup Standard recommends 55 grams of coffee per litre of water (approximately a 1:18 ratio), while most specialty coffee professionals brew between 1:15 and 1:17. A 1:15 ratio produces a stronger, more full-bodied cup; a 1:17 ratio produces a lighter, more delicate cup with more clarity. Cold brew uses a much higher coffee concentration (typically 1:5 to 1:8) before dilution. This calculator takes your coffee amount in grams, your chosen ratio (from 1:12 to 1:20, or a custom ratio), and outputs the water needed in grams, millilitres, and cups (using the standard US 240 ml cup definition).
Coffee ratio quick reference
| Ratio | Coffee (g) per cup (240 ml) | Strength |
|---|---|---|
| 1:12 | 20.00 | Very strong |
| 1:15 | 16.00 | Medium-strong |
| 1:16 | 15.00 | Medium (common default) |
| 1:17 | 14.12 | Medium-light |
| 1:18 | 13.33 | SCA Golden Cup Standard |
Coffee ratio: frequently asked questions
What is the standard coffee to water ratio?
The Specialty Coffee Association (SCA) recommends a brewing ratio of 1:15 to 1:17 (coffee to water by weight) for filter coffee. At 1:15, 20 grams of coffee brews with 300 grams of water. At 1:17, 20 grams brews with 340 grams of water. Ratios below 1:15 produce stronger coffee; ratios above 1:17 produce lighter coffee.
What ratio should I use for pour-over coffee?
Pour-over brewing methods such as Chemex, V60, and Kalita Wave work well between 1:15 and 1:17. A 1:15 ratio (stronger) highlights body and richness; 1:16 to 1:17 emphasises clarity and delicate flavour notes. Many specialty baristas use 1:16 as their default for balanced pour-over brews.
How many grams is a tablespoon of coffee?
A standard tablespoon of ground coffee weighs approximately 5 to 7 grams depending on the grind size. Coarser grinds weigh less per tablespoon than finer grinds. Specialty coffee professionals always measure by weight rather than volume for consistency. This calculator lets you enter grams directly for the most accurate results.
What is a 1:2 espresso ratio?
Espresso uses a much higher coffee-to-water ratio than filter coffee. A traditional espresso uses approximately 9 grams of coffee to produce 25-30 ml of espresso, roughly a 1:2.8 to 1:3.3 ratio. Specialty espresso commonly targets 1:2 (18 grams of coffee, 36 grams of espresso yield). This calculator is designed for filter brewing ratios, not espresso extraction.
How many cups does a given amount of coffee make?
This calculator uses 240 ml per cup as the standard US cup size. To calculate cups: take the total water weight in grams (approximately equal to ml), divide by 240. For example, 600 grams of water produces 2.5 cups of brewed coffee. The actual brewed volume will be slightly less than the water input because some water is absorbed by coffee grounds.
References
- Specialty Coffee Association: Coffee Standards.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.