What is the Coffee Ratio Calculator?
The Coffee Ratio Calculator turns your coffee dose and preferred brew ratio into the exact amount of water you should use. Baristas describe strength as a ratio of coffee to water, written as 1:X — for example 1:15 means one gram of coffee for every 15 grams of water. Because 1 ml of water weighs about 1 gram, the water figure in grams is essentially the same as millilitres.
How to use it
Enter the weight of coffee you plan to brew in grams, then enter your brew ratio (the X in 1:X). Common ranges are 1:15 to 1:17 for filter/pour-over, 1:13 to 1:15 for a stronger cup, and lower numbers for more intense brews. The calculator multiplies the two values and also estimates how many standard 8 oz cups that makes.
The formula explained
The math is simple: $$\text{Water} = \text{Coffee} \times \text{Ratio}$$. The ratio is dimensionless, so the answer comes out in the same unit as the coffee — grams. We then divide by 236.588 ml (one US cup) to give a rough cup count for serving.
Worked example
Suppose you weigh out 20 g of coffee and want a balanced 1:15 brew. $$\text{Water} = 20 \times 15 = \mathbf{300}\ \textbf{g}$$ of water, which is roughly 300 ml or about 1.27 standard cups. Pour 300 g of hot water over your 20 g of grounds and you have a clean, repeatable recipe.
FAQ
Is grams of water the same as ml? Practically yes — water has a density of ~1 g/ml at brewing temperatures, so 300 g ≈ 300 ml.
What ratio should I start with? 1:16 is a great all-rounder for pour-over. Lower the number for stronger coffee, raise it for a lighter cup.
Does this work for espresso? Espresso uses much tighter ratios (around 1:2). You can enter a ratio of 2 to size an espresso shot, though brew temperature and pressure matter too.
