Coffee strength is conventionally specified as a ratio of coffee to water by weight. This works out how much of one you need given the other and your chosen ratio.
How it works
Brew ratio
water (g) = coffee (g) × ratio
A ratio of 16 means 1:16 — one part coffee to sixteen parts water by weight. Lower numbers make a stronger brew, higher numbers a weaker one.
Why weight, not scoops or cups
A “scoop” of coffee varies with grind size, bean density and how packed the scoop is — the same scoop of a coarse grind and a fine grind of the same bean can differ in weight by a meaningful margin. Water, by contrast, is close enough to 1 gram per millilitre that measuring it by weight is both accurate and just as easy as measuring by volume — which is why specialty coffee brewing conventionally specifies both sides of the ratio by weight, sidestepping the scoop problem entirely.
How to use this calculator
- Choose whether you’re starting from a known coffee amount or a known water amount.
- Set your target ratio — roughly 15–17 is a common starting range.
- Read the other amount.
Frequently asked questions
What ratio should I use?
It’s a matter of taste and brew method — a lower ratio (like 1:14) gives a stronger brew, a higher one (like 1:17) gives a weaker one. Different brewing methods (espresso, pour-over, French press) also conventionally use different typical ranges.
Why does specialty coffee use weight instead of volume for coffee too?
For the same reason water is weighed — grind size and roast level both change how much a given volume of coffee actually weighs, so weight gives a far more repeatable result than a scoop or a tablespoon.
Does grind size affect the ratio I should use?
Not the ratio itself, but it affects extraction — a finer grind extracts faster, so the same ratio and brew time can taste different at different grind sizes. Ratio and grind size are separate variables that both affect the final cup.
Can I use this ratio for cold brew?
Cold brew conventionally uses a much more concentrated ratio (often closer to 1:4 to 1:8) since it’s typically diluted before drinking — check your specific method’s recommended starting ratio rather than using a hot-brew range.
Is 1 gram of water really 1 millilitre?
Very close, for practical kitchen purposes — pure water at room temperature is almost exactly 1 g/mL, which is why weighing water and measuring it by volume give effectively the same result for brewing purposes.
