One chart makes coffee-to-water ratios easy to calculate

Name the two quantities

This article uses dry coffee mass and water poured into a filter brewer. It does not use final beverage mass. Some water remains with the grounds and equipment, so the drink collected is not automatically equal to the water poured. Write the meaning beside the ratio before calculating.

Work from coffee to water

At 1:16, 15 g of coffee calls for 240 g of input water in the example: 15 multiplied by 16. A 20 g dose corresponds to 320 g, and a 30 g dose to 480 g. These are recipe quantities, not a claim that this ratio is ideal for every coffee or brewer.

Work backward from the desired input

If the recipe calls for 400 g of input water at 1:16, divide 400 by 16 to obtain 25 g of coffee. If your goal is a particular amount of finished beverage, account for the method’s retention rather than silently treating input water as cup yield.

Check three common arithmetic slips

First, 1:16 means sixteen units of the defined water quantity per unit of coffee; it does not mean sixteen units in total. Second, increasing 15 g of coffee to 20 g while keeping 240 g water changes the ratio to 1:12. Third, 240 g of input water is not a promise of 240 g in the cup. These mistakes are easy to avoid if you write coffee mass and input-water mass above the numbers before calculating. For another practice example, 22 g at 1:16 calls for 352 g of input water. The math is exact for those stated quantities.

Scaling the numbers does not scale the flow

A bigger dose changes the bed in the brewer. Pouring, grind and time may need a new baseline even when the ratio remains identical. Check brewer capacity and the method’s guidance before doubling a recipe. Use the arithmetic to set quantities, then observe how the actual brew behaves.

Practical check: what to observe

Work through the numbers using the stated units. The examples are illustrative; changing an input or an assumption can change what the result means.

1. Define water as input mass
2. Multiply coffee by the ratio
3. Check brewer capacity

Is 1:16 always better than 1:15?

No. A ratio is a starting recipe choice, not a quality ranking. Preference, coffee, brewer and technique can change which recipe you enjoy.

For more context, see the topic FAQ and glossary. A reference value or example should be read with its units, assumptions and product-specific conditions.