# How much coffee for my water?

Works out how much ground coffee to use for an amount of water, or how much water for your coffee, at a brew ratio such as 1:16, in grams, ounces, milliliters and cups.

- Page: https://www.acalculator.org/food/coffee-ratio-calculator
- JSON spec: https://www.acalculator.org/food/coffee-ratio-calculator.json
- Version: 058447606e81

## Default answer

Example with the default inputs (Start from Water, Water 16.9070113509215 fl oz, Ratio 1 : 16): Use 31.25 g coffee to 500 g water.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| from | Start from | The water you will brew with, or the coffee you have. |
| w | Water | The brewing water. |
| c | Ground coffee | The ground coffee you will use. |
| r | Ratio 1 : | Grams of water per gram of coffee: 16 means 1:16. Lower is stronger. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| result | Brew | Coffee and water at your ratio, to 4 significant figures. |
| coffeeG | Coffee (g) | Water grams ÷ ratio. |
| coffeeOz | Coffee (oz) | The coffee in ounces. |
| waterML | Water (mL or g) | Coffee grams × ratio; 1 mL of water weighs 1 g. |
| waterFloz | Water (fl oz) | The water in US fluid ounces. |
| cups | Water (8 fl oz cups) | The water in 8 fl oz cups. |
| strength | Coffee per liter (g/L) | 1,000 ÷ ratio grams of coffee per liter of water. |

## Method

For a 1:N ratio, coffee grams = water grams ÷ N and water grams = coffee grams × N, with 1 mL of water = 1 g. Strength = 1,000 ÷ N grams per liter.

## Assumptions

- The ratio is by weight, brewing water to dry ground coffee. Water is taken as 1 g per mL.
- The brewed coffee is less than the water you pour, because the grounds hold some back (about twice their weight).

## Worked examples

1. from = water, w = 0.001, r = 18 gives coffeeG = 55.555556, strength = 55.555556, result = 55.56 g coffee to 1000 g water. Source: Wikipedia, Coffee preparation (brew ratios of water to coffee often 15–18:1 by mass; SCA 55 g of coffee per liter of water), https://en.wikipedia.org/wiki/Coffee_preparation (retrieved 2026-10-03).
2. from = water, w = 0.0005, r = 16 gives coffeeG = 31.25, result = 31.25 g coffee to 500 g water. Source: Wikipedia, Coffee preparation (brew ratios of water to coffee often 15–18:1 by mass; SCA 55 g of coffee per liter of water), https://en.wikipedia.org/wiki/Coffee_preparation (retrieved 2026-10-03).
3. from = coffee, c = 0.02, r = 15 gives waterML = 300, waterFloz = 10.144207, cups = 1.268026. Source: Wikipedia, Coffee preparation (brew ratios of water to coffee often 15–18:1 by mass; SCA 55 g of coffee per liter of water), https://en.wikipedia.org/wiki/Coffee_preparation (retrieved 2026-10-03).

## FAQ

### What is a good coffee to water ratio?

Most brewing guides fall between 1:15 and 1:18 by weight: 15 to 18 g of water for each gram of coffee. 1:16 is a common middle. The Specialty Coffee Association’s standard of 55 g per liter is about 1:18.

### How much coffee for 500 mL of water?

At 1:16, 500 ÷ 16 = 31.25 g of ground coffee. At 1:15 it is 33.3 g; at 1:18 it is 27.8 g.

### How much water for 20 g of coffee?

Multiply by the ratio: at 1:15, 20 × 15 = 300 g of water, which is 300 mL or about 10.1 fl oz.

### Why weigh water in grams?

One milliliter of water weighs about one gram, so grams and milliliters are the same number. A kitchen scale makes the ratio exact and repeatable.

### Does the ratio change for French press or espresso?

French press and drip usually sit between 1:15 and 1:17. Espresso is much stronger, around 1:2 by the weight of the drink, so use a ratio of about 2 for it.

### Why do I get less coffee than the water I poured?

The wet grounds keep some water, roughly twice their own weight. 30 g of coffee holds back about 60 g, so 500 g of water gives about 440 g of brewed coffee.

## Sources

- Wikipedia, Coffee preparation: preferred brew ratios of water to coffee often fall in the range of 15–18:1 by mass; the SCA standard of 55 g of coffee per liter of water; 7 g of grounds for a 25 mL espresso. Retrieved 2026-10-03. https://en.wikipedia.org/wiki/Coffee_preparation
- NIST Special Publication 811, Appendix B.8: 1 US fluid ounce = 2.957353 × 10⁻⁵ m³; 1 oz (mass) = 28.349523125 g. Retrieved 2026-10-03. https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8