How it works
The ratio is by weight throughout, treating 1 ml of water as 1 g. Each method carries a fixed ratio: Pour over (V60) 1:16, Chemex 1:17, French press 1:15, AeroPress 1:14, Espresso 1:2, Moka pot 1:10, Drip / batch brewer 1:17 and Cold brew 1:8. The strength slider rescales it as ratio × (1 − strength ÷ 100) across plus or minus 15, so +15 on a V60 tightens 1:16 to roughly 1:13.6.
Start with the "I have…" select. "A target water amount" divides your figure by the ratio to give coffee; "A target coffee amount" multiplies it to give water; "A number of cups" multiplies your count by the Cup size select — 240 ml US mug, 180 ml SCA cup, 60 ml espresso double or 350 ml large mug — then divides. The grind, brew time and water temperature shown alongside come from the method itself, not from your numbers.
These ratios are fixed starting points, not a model of extraction: roast level, grind fineness, water mineralisation and brewer geometry all shift the cup and none are inputs here. Espresso is a special case, because its 1:2 is a dose-to-yield ratio — the figure the tool labels as water is really the liquid espresso in the cup, not what you put into the machine. In cups mode the g/oz selector is ignored.
Frequently asked questions
What is the best coffee to water ratio for pour over? +
The Pour over (V60) preset uses 1:16, so 500 g of water takes 31.3 g of coffee. Chemex and drip sit at 1:17 for a lighter cup and French press at 1:15. The strength slider moves any of them by up to 15 percent.
How much coffee do I need for a French press? +
Select French press for its 1:15 ratio, switch the input to a target water amount, and enter your carafe volume in grams. A 1000 g press takes 66.7 g of coarsely ground coffee, steeped for the four minutes the tool recommends.
What does the strength slider actually change? +
It multiplies the method's ratio by one minus the slider value over 100, across plus or minus 15. Positive values tighten the ratio and use more coffee per gram of water; negative values loosen it. Grind and brew-time recommendations do not move.
Why is espresso listed as 1:2? +
Because espresso is measured dose to yield rather than dose to water. A 1:2 ratio means 18 g of ground coffee producing 36 g of liquid in the cup, so the figure labelled water here is that yield, not what you feed the machine.
Can I measure by volume instead of weighing? +
Not accurately. Scoops vary with grind size, roast level and how the grounds settle, and the ratio here is strictly by weight with 1 ml of water treated as 1 g. A two-gram error per cup is the gap between weak and bitter.
The brew ratio, and where the common numbers come from
Brew ratio is coffee weight to water weight, and the filter range runs roughly 1:14 to 1:17 — stronger at the low end, more dilute at the high. 1:16 is a common default and 1:15 a common pour-over target. Espresso sits in a completely different regime around 1:2, which is why it is not on the same scale.
Ratio and grind size are the two variables that actually matter, and they are not interchangeable: ratio sets strength, grind sets extraction. Coffee that is weak *and* sour is under-extracted and wants a finer grind; coffee that is weak but pleasant simply wants more coffee.
Water weight, absorbed water, and why yields fall short
Ratios are by weight, and 1 ml of water weighs 1 g closely enough that volume and weight are interchangeable on the water side. The coffee side is not — beans vary in density with roast level, so scooping rather than weighing introduces exactly the error the ratio was meant to remove.
Spent grounds retain roughly twice their own weight in water, so a brew made with 60 g of coffee and 960 g of water yields well under 960 g in the cup. If you are targeting a finished volume rather than a brew ratio, add the absorbed water on top.
Water itself is the ingredient people ignore longest. Very soft or distilled water extracts poorly and tastes flat, and hard water scales equipment and mutes acidity.
