How to use this calculator
The brew ratio is the number of parts of water for one part of coffee by weight. It defaults to 1:16, a common starting point for pour-over and drip. Enter the coffee dose to get the water, or enter the amount of water your kettle or carafe holds to get the dose. To brew a specific mug size, enter the brewed amount you want; the calculator adds back the water absorbed by the grounds.
Use a kitchen scale: one milliliter of water weighs one gram, so the water field can be read as milliliters. Coffee is too variable by volume to scoop accurately — a "tablespoon" can be anything from 5 to 8 g depending on roast and grind.
The formula
- c
- ground coffee
- r
- brew ratio (water per 1 part coffee)
- w
- brewing water
- k
- water retained per gram of grounds
- b
- brewed coffee in the cup
Worked example
A pour-over recipe calls for 20 g of coffee at a 1:16 ratio.
- Water = 20 g × 16 = 320 g.
- Water kept by the grounds ≈ 2 × 20 = 40 g.
- Brewed coffee ≈ 320 − 40 = 280 g (about 9.5 fl oz).
Pour 320 g of water to end up with roughly 280 g of coffee in the cup.
Starting ratios by brew method
| Method | Ratio (water : coffee) |
|---|---|
| Espresso | 2 : 1 – 2.5 : 1 (brewed yield, not water) |
| AeroPress | 12 – 15 : 1 |
| Pour-over / drip | 15 – 17 : 1 |
| French press | 12 – 15 : 1 |
| Cold brew concentrate | 4 – 8 : 1 |
Assumptions and limits
- Spent grounds retain about twice their dry weight in water for drip and pour-over; French press and cold brew can retain slightly more.
- Water evaporation during brewing is ignored.
Frequently asked questions
What is the golden ratio for coffee?
The Specialty Coffee Association’s brewing guidance centers on about 55 g of coffee per liter of water, roughly 1:18. Many home brewers prefer 1:15–1:16 for a stronger cup.
How many grams of coffee for one cup?
For a 250 mL (8.5 fl oz) mug at 1:16, use about 17–18 g of coffee and 280 g of water to allow for absorption.
Does the ratio change with grind size?
The ratio controls strength; grind size controls extraction. Adjust grind first if the coffee tastes sour or bitter, then the ratio for strength.
Sources
Related calculators
- Brine CalculatorSalt and water for any brine percentage.
- Cups to Grams CalculatorConvert by ingredient, not just volume.
- Density CalculatorDensity, mass and volume.
More in Cooking calculators.