Coffee ratio calculator
Enter your water or your coffee, pick a ratio, get the other.
How much coffee per cup of water?
The Specialty Coffee Association's Golden Cup ratio is 55 grams of coffee per liter of water, give or take 10% — about 13 grams for an 8-ounce cup (237 mL) and 19.5 grams for a 12-ounce mug.
What does a 1:16 ratio mean?
1 part coffee to 16 parts water by weight: 20 g of coffee for 320 g of water. The SCA's 55 g per liter works out to about 1:18.
What water temperature is best?
The SCA recommends 200 °F ± 5° (93 °C ± 3°) at brewing — just off the boil.
How long should coffee brew?
The SCA's guide: 1–4 minutes for a fine grind, 4–6 minutes for drip, and 6–8 minutes for a coarse grind such as a French press.
Why measure coffee by weight?
A scoop of coffee weighs differently depending on the roast and grind. Grams on a kitchen scale give the same cup every morning.
How much water is that in ounces and cups?
One US fluid ounce of water weighs about 29.6 g, so 8 ounces is about 237 g. A 1:16 brew of 20 g of coffee takes 320 g of water, which is 10.8 fluid ounces.
Why is there less coffee in the cup than the water I poured?
The coffee grounds absorb some of the water, so the brewed coffee weighs less than the water you used. Use the water weight for the ratio, and expect less liquid in the cup.
What is the Golden Cup range in ratios?
The SCA's 55 g per liter, give or take 10%, is a range from 49.5 to 60.5 g per liter. As a ratio of coffee to water that is about 1:16.5 to 1:20.2, with the center at 1:18.2.
How the calculation works
A brew ratio of 1:n means one part of coffee for n parts of water by weight. The coffee needed is the water weight divided by n, and the water needed for a given amount of coffee is the coffee weight times n. The SCA Golden Cup standard is stated in grams of coffee per liter of water: 55 g per liter, with a tolerance of 10%. Because a liter of water weighs about 1,000 g, 55 g per liter is the same as one part coffee to 18.2 parts water. The calculator compares your ratio with that range.
Worked example
You want 750 g of water (about 25.4 fluid ounces). At 1:15 that takes 50 g of coffee, at 1:16 46.9 g, at 1:17 44.1 g and at 1:18 41.7 g. The SCA standard of 55 g per liter gives 750 × 55 ÷ 1,000 = 41.3 g, between the 1:17 and 1:18 results. A stronger brew like 1:15 is 21.2% more coffee than the Golden Cup amount, which is outside the ±10% tolerance.
Common mistakes
- Measuring coffee by scoops. The weight of a scoop depends on the roast and the grind. A scale gives the same strength every time.
- Changing the ratio when you want a stronger cup. A stronger cup can also come from a finer grind or longer contact time. If the coffee tastes bitter or harsh rather than weak, change the grind or the time before adding more coffee.
- Counting the water in the cup instead of in the brewer. The ratio uses the water you pour in, before the grounds absorb part of it.
Sources and related calculators
Ratio and temperature: the Specialty Coffee Association Golden Cup standard (55 g per liter, ±10%; 200°F ± 5°F water). Related: cooking measurement converter, recipe scaler and caffeine in body calculator.