Coffee Ratio Calculator

The SCA golden ratio is 1:15 to 1:18 — one gram of coffee per 15 to 18 grams of water. For most drip and pour-over methods, 1:16 (62.5g per liter) produces a well-balanced cup. Adjust toward 1:14 for stronger or 1:18 for lighter coffee.

For a standard 250ml (8.5 oz) cup at a 1:16 ratio, use 15.6 grams of coffee. For a stronger cup (1:14), use 17.9 grams. For a lighter cup (1:18), use 13.9 grams. These amounts produce properly extracted coffee within the SCA strength guidelines.

Standard espresso uses a 1:2 ratio — typically 18g of finely ground coffee yields 36g of liquid espresso in 25-30 seconds. Ristretto uses a 1:1 to 1:1.5 ratio for a shorter, more concentrated shot. Lungo uses 1:3 to 1:4 for a longer, milder extraction.

Coffee density varies dramatically by roast level, bean origin, and grind size. A level scoop of light-roast, finely ground coffee can weigh 50% more than the same scoop of dark-roast, coarsely ground coffee. A scale accurate to 0.1g ensures identical ratios every time.

Use a 1:5 to 1:8 ratio for cold brew concentrate, then dilute 1:1 or 1:2 with water, milk, or ice when serving. Start with 1:7 (about 140g coffee per liter of water) for a versatile concentrate that works straight over ice or diluted to taste.

Multiply the number of cups by 250ml to get total water, then divide by your ratio number. For 10 cups at 1:16: 10 × 250ml = 2,500ml water, then 2,500 ÷ 16 = 156g coffee. Remember that grounds absorb water, so your yield will be about 2,200ml of brewed coffee.

Starbucks recommends approximately 10g (2 tablespoons) per 180ml (6 oz), which equates to a 1:18 ratio — the lighter end of the SCA range. They use a relatively light ratio because their dark-roasted beans extract intensely, and this ratio balances the roast character.

At 1:15, you use more coffee per volume of water, producing a stronger, more full-bodied cup with heavier mouthfeel. At 1:17, less coffee means a lighter, more delicate brew with more noticeable acidity and floral notes. The difference is about 2g of coffee per 250ml cup.

Grind size does not change the ratio itself, but it changes how much is extracted at that ratio. Finer grinds expose more surface area, extracting more flavor (risking bitterness). Coarser grinds extract less (risking sourness). The ratio determines strength; grind size determines extraction balance.

Yes, the same ratio works as a starting point for any bean. However, you may want to adjust: light-roasted, high-altitude beans often taste better at 1:15 to 1:16, while dark-roasted beans may need 1:17 to avoid over-extraction bitterness. Let taste guide fine adjustments.

The standard AeroPress recipe uses approximately 1:11 to 1:16 depending on whether you prefer concentrate-style or American-style coffee. A common starting point is 17g coffee with 220ml water (about 1:13). The inverted method often uses a slightly higher dose.

At the SCA standard 1:16 ratio, you need 62.5g of coffee per liter of water. At 1:15 (stronger), use 66.7g per liter. At 1:17 (lighter), use 58.8g per liter. These amounts are for weight-based measurement using grams and milliliters.