Coffee to Water Ratio Calculator

Coffee-to-water ratio is the single most important variable in brewing great coffee. Too little coffee produces weak, watery results; too much produces bitter, astringent coffee. The specialty coffee industry uses grams of coffee per milliliters of water (or liters) as the standard measure.

Core ratio formula: Coffee (g) = Water (mL) × Brew Ratio

Or: Brew Ratio = Coffee (g) ÷ Water (mL)

Standard brew ratios by method:

• Drip (automatic): 1:15–1:17 (1 g coffee per 15–17 mL water)
• Pour-over (V60, Chemex): 1:15–1:17
• French press: 1:12–1:15 (a coarse grind extracts slowly, so the stronger ratio makes up for it over a four-minute steep)
• AeroPress: 1:10–1:14 (concentrated; often diluted after)
• Espresso: 1:2–1:3 (18–21 g coffee → 36–63 g espresso output)
• Cold brew: 1:8 ready to drink, 1:4–1:5 for a concentrate you dilute
• Moka pot: about 1:7, though the basket size sets this more than you do

Two of those need a word. For espresso the second number is not water going in, it is liquid espresso coming out, which is why 18 g of coffee makes 36 g at 1:2. And a moka pot is barely adjustable at all: you fill the basket level and the boiler to the valve, so the ratio is whatever the pot was built for. The 1:7 figure lets you check whether the pot you own is roughly on spec.

Volume to weight conversion: Water: 1 mL = 1 g (precise at room temperature) So 300 mL water = 300 g water.

Cups to milliliters, and the trap in the middle:

• 1 US cup = 237 mL (standard)
• 1 coffee “cup” on most drip machines = 150 mL
• 1 mug ≈ 350–400 mL
• 1 double espresso, measured as yield ≈ 60 mL

The second line is the one that catches people. The “12-cup” mark on a drip carafe means 12 × 150 mL, so 1.8 liters, not the 2.8 liters you would get from twelve US cups. Weigh coffee for a full pot as though it were twelve US cups and the result is undrinkably strong. Pick your cup size above and this calculator uses the one you actually mean.

Golden Ratio (Specialty Coffee Association standard): 55 g of coffee per 1 liter of water (1:18.2 ratio) This is the SCA’s recommended baseline for drip coffee — adjust by ±5 g to personal taste.

Worked example: You want to brew 600 mL of pour-over coffee using a 1:16 ratio.

Coffee needed = 600 mL ÷ 16 = 37.5 g (round to 38 g)

Grind: medium-fine (table salt texture for V60) Water temperature: 91–96°C (196–205°F) Total brew time: 3.5–4 minutes

For espresso: 18 g of coffee in, target 36 g espresso out (1:2 ratio), in 25–30 seconds extraction.

Strength vs extraction: Ratio controls strength (concentration). Grind size and water temperature control extraction (which flavor compounds are dissolved). Fixing ratio first, then adjusting grind, is the correct order for dialing in a recipe.