About this tool
Coffee-to-Water Ratio Calculator is a free, in-browser tool that turns your brew method and cup count into exact coffee and water amounts. Pick a method for a preset ratio or set your own, and the grams, tablespoons, millilitres and ounces update as you type. Nothing is uploaded — every figure is computed locally.
The math is direct: water (ml) = cups × cup size, coffee (g) = water ÷ ratio, where the ratio is the second number in 1:N (grams of water per gram of coffee). Grams are converted to tablespoons at roughly 5.3 g of ground coffee per tablespoon, and water to fluid ounces at 29.57 ml per ounce. Presets follow common guidance: drip and pour-over 1:16, French press 1:12, AeroPress 1:14, cold brew 1:8 and espresso 1:2.
Use it to scale a recipe up or down or to dial in strength: a smaller ratio number (like 1:12) gives a bolder cup, a larger one (like 1:17) a milder cup. The strength note reflects the ratio you chose, so you can nudge it to taste before you grind.