How the coffee-to-water ratio works
A coffee ratio describes how much water you pour for every gram of ground coffee. It is written as 1:n — one part coffee to n parts water by weight. Because 1 millilitre of water weighs about 1 gram, you can measure water in grams or millilitres and treat them as the same number.
Most filter and pour-over coffee lands between 1:15 and 1:18. A lower number such as 1:15 means more coffee per unit of water, so a stronger, bolder cup; a higher number such as 1:17 means a lighter, more delicate brew. Cold brew is different — it is made as a strong concentrate around 1:8, then diluted before drinking.
To go the other way, multiply your coffee by the ratio. Starting from 20 g of coffee at 1:16, you would pour 20 × 16 = 320 g of water. The calculator above does this in both directions and converts the result into cups and tablespoons for quick reference.
Coffee & water by cups
| Cups | Water (g/ml) | Coffee at 1:16 (g) | Coffee (tbsp) |
|---|---|---|---|
| 1 cup | 240 | 15 | 3 |
| 2 cups | 480 | 30 | 6 |
| 4 cups | 960 | 60 | 12 |
| 8 cups | 1920 | 120 | 24 |
Reference note: 1 cup ≈ 240 ml water and 1 level tablespoon of ground coffee ≈ 5 g. These are approximations — grind size, bean density and your taste all shift the ideal amount, so use a scale and adjust.
Frequently asked questions
- What is the best coffee-to-water ratio?
- A balanced brew is about 1 gram of coffee per 15 to 18 grams of water. A 1:16 ratio is a common starting point; use 1:15 for a stronger cup and 1:17 for a lighter one, then adjust to taste.
- How much coffee for 2 cups?
- Two cups is about 480 grams of water (1 cup is roughly 240 ml). At a 1:16 ratio that is about 30 grams of coffee — close to six level tablespoons.
- How many grams of coffee per cup?
- At a 1:16 ratio, one 240 ml cup of water needs about 15 grams of coffee. A stronger 1:15 ratio uses about 16 grams, and a lighter 1:17 ratio uses about 14 grams.
- What ratio for cold brew?
- Cold brew uses a strong concentrate, commonly around 1:8 coffee to water. You then dilute the concentrate with water or milk to taste before serving.
- How many tablespoons is 30 grams of coffee?
- One level tablespoon of ground coffee is roughly 5 grams, so 30 grams is about 6 tablespoons. Weighing is more accurate than measuring by spoon.
- Should I weigh coffee or use scoops?
- Weighing with a scale is more consistent because a scoop varies with grind size and bean density. Without a scale, estimate about 5 grams per level tablespoon and adjust to taste.