Coffee Ratio Calculator

Coffee brewing is a ratio, and the ratio is expressed as one part coffee to n parts water by weight. A 1:16 ratio means 16 grams of water for every gram of coffee — so 500 grams of water needs 31 grams of coffee.

It works by weight rather than volume because a gram of water is a millilitre, which makes the arithmetic trivial, and because a scoop of coffee can vary by 20% depending on the grind and how it settles. Weighing both sides is the single change that makes coffee consistent.

Espresso inverts it. Rather than starting from the water, you start from the dose in the basket and control the yield in the cup: an 18 gram dose at 1:2 pulls 36 grams of espresso. The ratio is the same idea, measured in the opposite direction.

1. Step 1 Total water water_g = cups × cup_size_ml 1 ml of water weighs 1 g, so millilitres and grams are interchangeable here.
2. Step 2 Coffee coffee_g = water_g ÷ ratio V60 and drip 1:16, French press and AeroPress 1:15, Chemex 1:16.5, moka 1:10, cold brew concentrate 1:5.
3. Step 3 Strength adjustment effective_ratio = base_ratio − strength Lowering the ratio means less water per gram of coffee, which is a stronger cup.
4. Step 4 Espresso, in reverse yield_g = dose_g × ratio An 18 g dose at 1:2 gives 36 g in the cup, ideally in 25–30 seconds.
5. Step 5 Tablespoon approximation tbsp ≈ coffee_g ÷ 5.5 Deliberately rough — a tablespoon of coffee is 5 to 6 grams depending on grind.

Example: two 240 ml mugs of pour-over is 480 g of water. At the V60 default of 1:16 that is 30 grams of coffee, or about 5.5 level tablespoons.

• The default ratios are widely-used starting points rather than rules: V60 and drip 1:16, Chemex 1:16.5, French press and AeroPress 1:15, moka pot 1:10, cold brew concentrate 1:5, espresso 1:2. Taste is the real arbiter and everyone lands somewhere slightly different.
• Water is treated as 1 gram per millilitre, which is accurate enough for brewing at any temperature you would use.
• The tablespoon conversion of 5.5 grams is approximate and can be 15% out either way depending on grind size, bean density and how the spoon is filled. It is offered for people without a scale, not as a substitute for one.
• Brew water absorbed by the grounds is not deducted. Coffee retains roughly twice its own weight in water, so a 30 gram dose keeps about 60 grams — meaning a 500 gram brew yields around 440 grams in the cup.
• Grind size guidance is generic. The correct grind depends on your specific grinder, the bean, its roast level and how fresh it is, and dialling it in is a matter of tasting and adjusting.
• Cold brew ratios produce a concentrate meant to be diluted. Ready-to-drink cold brew is typically brewed at 1:12 to 1:15 instead.
• Espresso yield assumes a normale shot at 1:2. Ristretto runs around 1:1.5 and lungo 1:3, both of which taste substantially different from the same dose.
• Water quality is ignored and matters more than most people expect. Very soft or heavily softened water extracts poorly, and very hard water scales equipment and mutes acidity.