Coffee-to-Water Ratio Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/5/2026
The amount of coffee is calculated as mass = (water volume in liters) × coffee-to-water ratio in g/L. For 250 mL of water at a ratio of 60 g/L, you need 15 g of ground coffee.
Explanation
The coffee-to-water ratio is the relationship between the mass of ground coffee and the volume of water used for brewing, generally expressed in grams of coffee per liter of water. The Specialty Coffee Association (SCA) defines a reference standard, the 'Golden Cup', at 55 g/L with a ±10% tolerance (that is, 50 to 60 g/L) to achieve a balanced extraction with filter methods; many professional baristas use 60 g/L as a simple mental benchmark. This ratio remains a starting point, not an absolute rule: a stronger coffee will call for a higher ratio (more coffee for the same volume of water), a lighter coffee a lower ratio. The brewing method also influences the optimal ratio: espresso, for example, uses a much more concentrated ratio than filter coffee, outside the scope of this calculator, which is designed for brewing or filter methods (drip coffee maker, French press, V60).
Example: preparing a 250 mL cup
Inputs
Water volume: 250 mL. Ratio: 60 g/L.
Calculation
Coffee mass = (250 ÷ 1000) × 60 = 0.25 × 60 = 15 g.
Result
You need 15 g of ground coffee for this 250 mL cup at the chosen ratio.
Frequently asked questions
Which ratio should I choose if I prefer stronger coffee?
Increase the ratio (more grams of coffee per liter of water): a ratio of 70 to 80 g/L gives a stronger coffee than a ratio of 50 to 55 g/L. Conversely, lower the ratio for a lighter coffee. The range recommended by the SCA standard (50-60 g/L) remains a good starting point to adjust to taste.
Does this ratio work for espresso?
No, this calculator is designed for brewing and filtration methods (drip coffee maker, French press, V60, Chemex), where the ratio is measured in grams per liter of water. Espresso uses a very different ratio, generally expressed as a direct relationship between the mass of coffee and the mass of the resulting beverage (often close to 1:2), and a much smaller amount of water.
Does the grind size affect the ratio to use?
The coffee-to-water ratio remains independent of the grind size, but the grind affects extraction speed: a finer grind extracts faster (suited to a short contact time), a coarser grind more slowly. For the same ratio, a grind poorly suited to the method can give over-extracted (bitter) or under-extracted (sour and flat) coffee, regardless of the amount of coffee used.