Cold brew is forgiving about almost everything except the ratio of coffee to water. This calculator works that out for any batch: enter the water you plan to use and a ratio, and it gives the coffee dose; enter the dose and it estimates how much liquid you will actually get back, how far a concentrate stretches once diluted and how many servings the batch makes. Every result shows its formula, and nothing you enter leaves your browser.
Use weights and volumes you can verify. The calculator shows its formulas and keeps every input in your browser.
Coffee dose from water and ratio
Estimated yield, dilution, and servings
Yield = 1,000 − (125 × 2) = 750 ml. Final volume = 750 × (1 + 0) = 750 ml.
What this calculator does not predict
- Flavor, extraction, strength, or an ideal recipe
- Caffeine or nutritional content
- Actual filter loss, evaporation, sediment, or coffee retention
- Shelf life, food safety, or compatibility with a specific brewer
One milliliter of water is treated as one gram for ratio arithmetic. Retention is an editable estimate, not a measured property of your coffee. Follow the product manual and applicable food-safety guidance.
Choosing a ratio
Ratios are written as water to coffee by weight. A concentrate meant for diluting usually sits around 1:4 to 1:5; a ready-to-drink batch you pour straight over ice usually sits around 1:8 to 1:12. The presets cover those ranges. If your coffee tastes weak, tighten the ratio before you lengthen the steep; if it tastes harsh or muddy, loosen it or check that your grind is coarse enough. Our guide to cold brew ratios goes deeper.
Why the yield is smaller than the water you added
Wet grounds hold on to water, so a batch never returns everything you poured in. The calculator subtracts an estimated amount of retained water per gram of coffee — about 2 ml by default — and you can change that figure to match what your own brewer and filter hold back. That is also why a concentrate is usually diluted around one-to-one at serving: the strength you taste depends on both the brewing ratio and the dilution.
Weigh, don’t scoop
Ground coffee varies in density, so a scoop of one coffee can weigh noticeably more or less than a scoop of another. A kitchen scale makes the ratio repeatable, which is the whole point of using one. For grind size and steep times, see cold brew grind size and how to make cold brew concentrate; for gear, our cold brew maker guide and cold brew coffee guide.