Coffee strength comes down to one number: how much water you use for each gram of coffee. Get that ratio right and adjust grind and time for taste, and the same beans will taste consistent from one morning to the next. This calculator converts any brew size into grams and tablespoons of coffee, or tells you how much water to use for the coffee you have on hand.
How to use the coffee ratio calculator
- Pick a brew method. Each comes with a typical ratio, or choose Custom ratio and type your own.
- Choose what you know: how much coffee you want to make, or how much ground coffee you have.
- Enter the water (in 8-oz cups, coffee-maker cups, fluid ounces, milliliters or liters) or the coffee (in grams, ounces or level tablespoons).
- Read the coffee or water needed, the amount that ends up in your cup, and the same brew at every other ratio.
Coffee ratio formula
A ratio of 1:16 means 16 grams of water for every gram of coffee. Since 1 mL of water weighs 1 gram:
For espresso the ratio compares the dry dose with the liquid shot, so 18 g of coffee at 1:2 gives a 36-gram shot.
Worked example
You want to brew 600 mL of pour-over at the standard 1:16:
Coffee = 600 ÷ 16 = 37.5 g, about 7½ level tablespoons.
The grounds hold back about 2 × 37.5 = 75 mL, so you get roughly 525 mL in the pot.
At a stronger 1:15 the same water needs 40 g; at the SCA's 1:18, about 33 g.
Ratios by brew method
| Method | Typical ratio | Notes |
|---|---|---|
| SCA Golden Cup | 1:18 (55 g/L) | Brewing standard for drip |
| Pour-over or drip | 1:15 – 1:17 | 1:16 is a balanced starting point |
| French press | 1:12 – 1:15 | Coarse grind, about 4 minutes |
| AeroPress | 1:11 – 1:13 | Often diluted after pressing |
| Moka pot | 1:7 – 1:10 | Strong, close to espresso |
| Cold brew, ready to drink | 1:8 | Steep 12–24 hours in the fridge |
| Cold brew concentrate | 1:4 – 1:5 | Dilute about 1:1 with water or milk |
| Espresso | 1:2 (dose to yield) | 1:1.5 ristretto, 1:3 lungo |
Getting the cup you want
Weigh rather than scoop
A level tablespoon of ground coffee weighs roughly 5 grams, but dark roasts, fine grinds and heaped scoops vary by 30% or more. A small kitchen scale is the single best upgrade for consistency.
Change one thing at a time
If the coffee is too weak, tighten the ratio (less water per gram). If it is strong but sour, the ratio is fine and the grind should be finer. The SCA describes a well-extracted brew as dissolving 18–22% of the coffee, which shows up as a balanced, sweet cup.
Know your cup size
Many automatic coffee makers mark their carafe in 5- or 6-ounce cups, so a 12-cup machine holds about 60 ounces, not 96. Choose coffee-maker cups in the water unit to match the markings.
Curious how much caffeine is in that pot? Try the caffeine calculator. The ratio calculator handles other proportions, and the milliliters to ounces converter helps with mug sizes.
Frequently asked questions
What is the golden ratio for coffee?
The Specialty Coffee Association's Golden Cup standard calls for about 55 grams of coffee per liter of water, which is roughly 1:18. Many home brewers prefer a slightly stronger 1:15 to 1:17.
How many tablespoons of coffee per cup?
For an 8-ounce mug at 1:16, you need about 15 grams of coffee, which is roughly 3 level tablespoons of medium-ground coffee. Coffee makers often define a cup as 5 or 6 ounces, so their scoops-per-cup advice is smaller.
Does the ratio change with grind size?
The ratio sets strength; grind and brew time set extraction. If coffee tastes sour or thin at a good ratio, grind finer or brew longer; if it tastes bitter or harsh, grind coarser or shorten the brew.
Why is the brewed coffee less than the water I used?
Spent grounds hold onto water, about twice their own weight in drip and pour-over brewing. Brewing 500 mL of water through 31 g of coffee leaves roughly 440 mL in the cup.