Coffee to Water Ratio Calculator

How it is calculated

Enter the water in millilitres and the brew ratio as the number after the colon in 1:x. The tool treats 1 ml of water as 1 g and computes coffee (g) = water ÷ ratio. It also converts the dose to tablespoons with tablespoons = coffee (g) ÷ 5.3, assuming about 5.3 g of ground coffee per level tablespoon. Both results have one decimal. Water must be above zero. If the ratio is left empty, zero or negative, the tool uses 1:16. A larger number after the colon gives a weaker brew, because the same water is divided by a bigger number. Tablespoon weights vary with grind and roast, so the spoon figure is only a rough guide and the gram figure is the one to rely on.

Common mistakes

• Entering the ratio as 15:1 or as the coffee share. The field is the water part of 1:x, so 1:15 is entered as 15.
• Typing the water in cups or ounces. The field is millilitres, so convert first, or the dose will be wrong.
• Expecting a larger number to make stronger coffee. A higher x means more water per gram of coffee, so the brew is weaker.
• Trusting the tablespoon figure over the scale. A level tablespoon of a dark, coarse grind weighs less than one of a fine grind.
• Using the brewed volume of coffee in the cup instead of the water poured in. Grounds absorb some water, so the cup is smaller than the water you enter.