Coffee Ratio Calculator — grounds to water
Dial in your brew: enter coffee grams or water millilitres and get the other at 1:15, 1:16, 1:17 or a custom ratio — in your browser.
🔒 Runs entirely in your browser. Your input and output are never sent to a server or stored — fully private.
Pick a brew ratio, then enter coffee or water — the other side updates live.
Ratio is coffee : water by weight (1 ml water ≈ 1 g). Cold brew 1:8 makes a concentrate — dilute to taste. 1 cup ≈ 240 ml.
About this tool
Dialling in coffee is mostly a matter of ratio, and this calculator handles the arithmetic: pick a coffee-to-water ratio such as 1:15, 1:16 or 1:17, enter either the coffee dose or the water amount, and get the other instantly. Method presets cover pour-over, French press, AeroPress and drip machines, and a cold-brew mode computes concentrate strength plus how much to dilute per glass. Scale a recipe from one cup to a full carafe without mental math. All calculations run locally in your browser — nothing is sent to any server.
Frequently asked questions
Which ratio should I choose — 1:15, 1:16 or 1:17?
The ratio sets strength: less water per gram of coffee means a more concentrated cup. 1:15 gives a rich, heavier brew, 1:16 is the popular middle ground for pour-over, and 1:17 tastes lighter and more tea-like. There is no single correct answer — specialty guides commonly recommend anywhere from 1:14 to 1:18. Start at 1:16, then move one step toward 1:15 if the cup feels thin, or toward 1:17 if it feels heavy or muddy.
My coffee still tastes bad at the "right" ratio — why?
Because ratio and extraction are two different dials. The ratio controls how much water passes through the coffee (strength), while grind size, water temperature and contact time control how much flavour is pulled from the grounds (extraction). A sour, thin cup usually means under-extraction — grind finer or brew longer — while bitterness suggests over-extraction — grind coarser or shorten the brew. Fix extraction with grind and time first; only change the ratio when the balance is right but the strength is not.
How does the cold-brew concentrate mode work, and is my recipe kept private?
Cold brew is usually made as a concentrate at a much stronger ratio, around 1:5 to 1:8, then diluted with water, milk or ice at serving time — often one part concentrate to one or two parts water. The mode computes both steps: how much coffee and water to steep, and the dilution per glass for your target strength. And yes, it stays private: every calculation is plain JavaScript running in your browser, so your doses and recipes are never uploaded or stored.