The Calculator Helper

Coffee Ratio Calculator

Work out how much coffee to use for your water and brew strength.

ml
1 :

Lower is stronger; 15–18 is typical.

Ground coffee
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Cups (250 ml)
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Coffee per cup
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By weight, 1 ml of water ≈ 1 g. Adjust the ratio to taste and match your grind to the brew method.

Strength is a ratio

Good coffee starts with the proportion of coffee to water. Expressed as 1 : n by weight, a smaller n means more coffee per unit of water and a stronger brew; a larger n means a milder cup.

coffee = water ÷ ratio

Because a millilitre of water weighs about a gram, you can read the water in millilitres and the coffee in grams. Dial in a ratio you like and it scales to any batch size, from a single cup to a full pot.

Worked example

For 500 ml of water at a 1:16 ratio, use about 31 g of ground coffee — a balanced strength. That makes roughly two 250 ml cups, at around 16 g of coffee per cup.

Consistency in the cup

The quickest route to repeatable coffee is to weigh your dose and water and keep the ratio fixed. Once that is steady, you can change one variable at a time — grind, time, temperature — and actually taste the difference.

Barista basics

  • Weigh, don’t scoop. Scoops vary; grams don’t.
  • Ratio sets strength. Grind and time set extraction and flavour.
  • Start at 1:16. Then nudge stronger or milder to taste.

Frequently asked questions

What is the "golden ratio"?
A common starting point of about 1 part coffee to 15–18 parts water by weight, often quoted as 1:16. It is a guide, not a rule — adjust to taste.
Should I weigh coffee and water?
Weighing both in grams is the most consistent way to brew, since 1 ml of water is about 1 g. A small kitchen scale makes results repeatable.
How do I make it stronger or weaker?
Lower ratios (more coffee per unit of water, like 1:14) brew stronger; higher ratios (like 1:18) brew milder. Change the ratio rather than over- or under-filling.
Does grind size matter too?
Yes. Ratio sets strength, but grind size and brew time affect extraction and flavour. Finer grinds extract faster; match the grind to your brewing method.