Coffee Ratio Calculator
Pick your brew method to load its typical coffee-to-water ratio — or type your own — then enter either the water you plan to pour or the coffee you have on hand. You get exact grams, the tablespoon equivalent, how many 6 oz cups it makes, and the grind size that suits the method.
How the math works
Ratios are mass to mass: 1:16 means 1 gram of ground coffee for every 16 grams (millilitres) of water. Since 1 ml of water weighs 1 g, you can read millilitres straight off a scale. The Specialty Coffee Association's golden-cup standard of 55 g per litre works out to 1:18; most home brewing lands happily between 1:15 and 1:18, and 1:16 is the safe default for pour-over and drip.
Weight beats volume because a tablespoon of ground coffee can weigh anywhere from 3 g (coarse, fluffy light roast) to 7 g (fine, dense dark roast). A cheap 0.1 g kitchen scale removes the biggest source of day-to-day inconsistency in a cup — which is why the calculator shows grams first and tablespoons only as a fallback.
Ratios by method, and why they differ
Pour-over and drip (1:16–1:17) pass water through the bed once over a few minutes, extracting 18–22% of the coffee's soluble mass; 1:16–1:18 lands that extraction at a pleasant strength. French press (1:15) steeps everything together and is usually served with milk or drunk in smaller cups, so many brewers nudge it stronger. Moka pot (1:10) works with a fine grind and pressurised steam, brewing a small, intense cup. Espresso (1:2) is a different language entirely: 18 g in, about 36 g of beverage out, in 25–30 seconds under 9 bars. Cold brew (1:5–1:8) brews a concentrate meant to be diluted 1:1 with water or milk before serving — if you drink it straight over ice without diluting, you are effectively brewing at a hot-brew ratio already.
Grind size by method
The ratio controls strength; the grind controls how fast the water extracts. As a starting point: extra-fine for espresso, fine for moka, medium for pour-over and drip (like coarse sand), coarse for French press (like sea salt), extra-coarse for cold brew. If your coffee tastes sour and thin, grind finer or brew longer — sourness is under-extraction. If it tastes bitter and drying, grind coarser or shorten the brew. Change one variable at a time, and change the grind before you change the ratio.
FAQ
- Is 1:15 or 1:17 stronger?
- 1:15. The smaller the second number, the more coffee per unit of water and the stronger the cup. Moving from 1:16 to 1:15 is about a 6% dose increase — noticeable, but not dramatic. Going from 1:16 to 1:14 is where most people say "now it tastes strong".
- How many grams of coffee for 8 cups on my drip machine?
- A machine's "cup" is 6 fl oz, so 8 cups is 1,416 ml. At 1:16 that is about 88 g of ground coffee — roughly 17–18 level tablespoons, or a bit more than half of a standard 12 oz bag. The calculator converts it for you if you type the cups.
- My scale maxes out at 500 g — can I still weigh the water?
- Yes: most pour-over brewers and mugs are well under 500 g when empty, and you can tare between additions, or weigh the kettle before and after pouring. For French press and cold brew, just pour by volume from a measured jug — millilitres and grams are interchangeable for water.
- Should I change the ratio for decaf or dark roast?
- Darker roasts are more soluble and taste stronger at the same dose, so many brewers move them toward 1:17; light roasts are denser and brighter and often taste best at 1:15–1:16. Decaf behaves like its roast level, not like a special case.
- How do I scale a recipe for iced coffee?
- Brew at a concentrated ratio such as 1:10–1:12 with part of the water replaced by ice: weigh the ice as water in the ratio, add it to the server, and brew directly onto it. The melting ice dilutes the brew to normal strength while flash-chilling it.
Ratios on this page are starting points drawn from SCA brewing standards and common roaster recommendations. Your water, grinder and roast all shift the ideal dose — adjust one variable at a time and taste as you go.