Coffee Ratio Calculator
Work out how much water goes with your coffee, or how much coffee a given amount of water needs, at the brew ratio you choose.
Result
Enter brew ratio, water per 1 part coffee to see the result.
https://calcgallery.com/recipe/coffee-ratio-calculator/
Results are arithmetic on the figures you enter. Cooking times are estimates: ovens, cuts and starting temperatures vary, so check doneness with a thermometer. Safe temperatures are the USDA's; guidance differs by country, so check your own. Read the full disclaimer
How to use the Coffee Ratio Calculator
- Choose whether you are starting from the coffee you have or the amount of water you want to brew.
- Enter the brew ratio as the second number of 1 to something. A recipe that says 1:16 means 16 grams of water for every gram of coffee, so enter 16.
- Read the water in grams and millilitres, or the coffee to weigh out.
One ratio, two directions
A brew ratio compares the weight of ground coffee with the weight of water poured over it. Written 1 : R, it multiplies one way and divides the other:
water = coffee × Rcoffee = water ÷ Rwater volume = water mass ÷ density of waterWorking by weight is what makes a ratio repeatable. A scoop of coffee can weigh quite different amounts depending on the grind and the roast, while 20 grams is always 20 grams. When you start from the water, the page turns your volume into a weight first, then divides.
Scaling a brew up or down
Keeping the ratio fixed is how a recipe for one cup becomes a recipe for a carafe. Enter the new amount of coffee, or the new amount of water, with the same ratio, and the other side follows. Brew time and grind may still need adjusting for a much larger batch; those depend on the brewer rather than on arithmetic.
For other kitchen quantities scaled by the same idea, the recipe scaling calculator adjusts a whole ingredient list at once.
With your numbers
- Ratio 1 : 16
- Water = 20 g × 16 = 320 g
Quick reference
This is the water you pour. The cup holds less, because the wet grounds keep some of it back.
| Example | Result |
|---|---|
| 20 g at 1:16 | Water, by weight: 320 g |
| 15 g at 1:17 | Water, by weight: 255 g |
| 60 g at 1:15 | Water, by weight: 900 g |
| 500 mL at 1:15 | Ground coffee: 33.3 g |
| 12 fl oz at 1:16 | Ground coffee: 22.2 g |
| 30 g at 1:18 | Water, by weight: 540 g |
Where the numbers come from
The fixed figures this calculator relies on, and the published source each one was checked against. How the calculators are built and checked
1 source
NIST Chemistry WebBook, water at 4 °C and 0.101325 MPa: 999.9749 kg/m³ (IAPWS-95), https://webbook.nist.gov/cgi/fluid.cgi?ID=C7732185, rounded to the conventional 1000 kg/m³ of NIST SP 811 (2008) Appendix B, centimeter of water, conventional = 98.0665 Pa.
Used for
- The conventional density of water, 1000 kg/m³. Pure water at 4 °C, its densest, is 999.97 kg/m³.
Common questions about the Coffee Ratio Calculator
- What does a coffee ratio like 1:16 mean?
- One part coffee to sixteen parts water, by weight. 20 grams of ground coffee takes 20 × 16 = 320 grams of water. Because it is a ratio, the units do not matter as long as both sides use the same one.
- What ratio should I use?
- The one your recipe, brewer or taste calls for. Ratios vary with the brewing method, the grind and the coffee, so the page does not suggest one. Start from a recipe you like and adjust from there: a smaller second number makes a stronger cup.
- Why weigh the water instead of measuring it?
- A scale reads the same grams whatever cup or jug you use. If you prefer to measure by volume, the page converts at 1 gram per millilitre, the conventional density of water. Hot water is slightly less dense, so a measured volume of it weighs a little less.
- Why is there less coffee in my cup than water I poured?
- The wet grounds hold some water back, and some evaporates. The ratio counts the water you pour, so the cup comes out smaller than the water figure on this page.