Coffee to Water Ratio Calculator

About this calculator

The right coffee-to-water ratio is the single biggest variable in how your brew tastes. Too much water and it is weak and flat; too little and it turns bitter and over-extracted. The Specialty Coffee Association (SCA) defines its "Golden Cup" standard at roughly 55 g of coffee per litre of water — a ratio near 1:18. This calculator lets you dial in any ratio from a strong brew (1:12) to a light, tea-like cup (1:20) and gives you the exact coffee dose in grams for your chosen volume or number of cups.

How to read your results

The headline figure is the coffee dose in grams. Enter how much water you are using (in grams or millilitres, which are equal for water) OR the number of cups (1 cup = 240 g of water). Then set your ratio: a lower number (e.g. 1:12) means more coffee — stronger brew; a higher number (e.g. 1:18) means less coffee — lighter, brighter cup. Use the brew-method preset chips to jump straight to a standard starting point.

Worked example

6 cups of water (1 440 g), drip method at 1:16.

90 g of coffee — about 9 standard tablespoons or 9 scoops if your scoop holds 10 g. At the SCA golden ratio (1:18.18) the same 6 cups would need about 79 g.

Frequently asked questions

What is the SCA golden ratio?

The Specialty Coffee Association recommends 55 g of ground coffee per litre of water (a ratio of about 1:18.18) as its "Golden Cup" standard — the sweet spot where most tasters find the brew balanced, neither weak nor bitter. It is a starting point, not a rule; adjust to your own taste.

Why measure in grams instead of tablespoons or scoops?

Coffee density varies with grind size and bean type, so a tablespoon can hold anywhere from 5 g to 12 g. Grams are consistent regardless of grind, making recipes repeatable. If you only have a scoop, a standard coffee scoop holds about 10 g of medium-ground coffee — but weigh it once to know for sure.

Does the ratio change for different brew methods?

Yes. Espresso uses far less water and a finer grind, so its ratio (1:2 or so) is not covered here — this calculator is for immersion and filter methods. For drip and pour-over a 1:15 to 1:17 range is typical; French press tends toward 1:12 to 1:15 because the immersion style extracts differently; cold brew is often 1:4 to 1:8. The preset chips set a common starting point for each method.

How strong or weak does a given ratio taste?

As a rough guide: 1:12–1:14 is strong (barista or café-style); 1:15–1:17 is everyday medium-strength; 1:17–1:20 is lighter and often described as "tea-like." Specialty roasters and the SCA sit around 1:15–1:18. Start in the middle and adjust one unit at a time to find your preference.

How it's calculated

The formula is simple: coffee (g) = water (g) ÷ ratio. The SCA Golden Cup standard targets 55 g of coffee per 1 000 g of water, which equals 18.18 g of water per gram of coffee — rounded to "1:18" in casual usage. Cup conversion assumes 1 US cup = 240 mL ≈ 240 g of water (density ≈ 1 g/mL at brewing temperature). Grams per litre = (coffee g ÷ water g) × 1 000.