How to use the coffee to water ratio calculator
- Enter the amount of water you plan to brew and choose the unit: fluid ounces, cups of 8 fl oz, milliliters or liters.
- Set the ratio as grams of water per gram of coffee. The default 16 means 1 part coffee to 16 parts water.
- Set how many grams a level tablespoon of your ground coffee weighs, so the result can be shown in spoons. Weigh it once and keep the number.
- Read the ground coffee in grams, ounces and tablespoons, and the coffee per 8 fl oz cup.
Formula
Water in mL = amount x milliliters per unit
Coffee in grams = water in mL / ratio
Tablespoons = coffee grams / grams per tablespoon
1 fluid ounce = 29.5735295625 mL; 1 ounce = 28.349523125 g
One milliliter of water weighs about one gram, so water in grams and milliliters are treated as equal.
Worked example
To brew 24 fluid ounces (710 mL) at a 1:16 ratio you need 709.76 / 16 = 44.4 g of coffee. At 5 g per tablespoon that is 8.9 tablespoons, or 1.56 oz.
A liter of water at 1:15 needs 66.7 g of ground coffee. Each 8 fl oz cup at 1:16 uses 14.8 g.
Start from a ratio, then adjust by taste
A ratio between about 1:15 and 1:17 is an example starting range for filter coffee. Use a lower number, such as 15, for a stronger cup and a higher one, such as 17, for a milder cup. These are taste preferences, not standards, so change the ratio until it suits you and note it down.
Why weigh coffee
Scoops and tablespoons vary with grind size, roast and how you fill them. Weighing grams is repeatable. If you measure by spoon, weigh a level tablespoon of your own coffee and enter that figure. See also the cooking measurement converter and the ingredient grams to cups converter.
Brew size versus cup size
The water you pour is more than the coffee you drink, because the grounds hold back some liquid. If you want a full 12 fl oz in the cup, brew a little extra. The unit converter helps with other volume conversions and the air fryer conversion calculator covers another kitchen conversion.
Assumptions and limits
- The ratio and the grams per tablespoon are inputs. Neither is a standard, and both depend on your taste, grind and coffee.
- Water is treated as weighing one gram per milliliter.
- The result is the water poured, not the volume of brewed coffee.
- Grind size, water temperature and brew time, which also affect strength, are not modeled.
Frequently asked questions
What is a good coffee to water ratio?
The default is 1:16 by weight, and you could try anything from 1:15 to 1:17 as a start. The best ratio is the one you like, so adjust in small steps until the cup tastes right.
How much coffee for 12 cups?
Twelve 8 fl oz cups is 96 fl oz, or about 2,839 mL. At 1:16 that is about 177 g of ground coffee. Enter 12 cups to see it in tablespoons.
How many tablespoons of coffee per cup?
At 1:16 and 5 grams per tablespoon, one 8 fl oz cup needs about 3 tablespoons. Weigh your own tablespoon for a precise answer.
Does the ratio change for cold brew?
Often yes. Cold brew is commonly made stronger and diluted later, so the starting ratio can be much richer. Enter your own number and adjust.