Sixty grams of coffee per litre of water is the number most filter brewing is built around, which works out at 1:16 and, for a normal mug, a rounded 15 g. That single figure fixes more bad coffee than any equipment upgrade, because almost everyone who says their machine makes weak coffee is under-dosing it. The calculator above adjusts that sum for the method you are actually using; below is where the numbers come from.
What a brew ratio is
A ratio is coffee to water by weight: 1:16 means one gram of coffee for sixteen grams of water. Water weighs a gram per millilitre closely enough for kitchen purposes, so 500 ml of water is 500 g, and the sum is one division. Working by weight rather than by scoops is the whole point — a level scoop of a light roast and a level scoop of a dark one differ by several grams, and beans lose density as they age.
A tighter ratio (1:14) gives you a stronger, heavier cup; a wider one (1:17) gives a lighter, more transparent one. Neither is correct. What is not a taste decision is grind size: if a cup tastes thin at the right ratio, the answer is usually a finer grind, not more coffee.
Working ratios by method
| Method | Usual ratio | Working window |
|---|---|---|
| Espresso | 1:2 | 1:1.5 to 1:3 |
| Pour-over (V60) | 1:16 | 1:15 to 1:17 |
| Chemex | 1:16 | 1:15 to 1:17 |
| French press | 1:15 | 1:12 to 1:17 |
| AeroPress | 1:14 | 1:10 to 1:17 |
| Moka pot | 1:8 | 1:7 to 1:10 |
| Filter machine | 1:16.5 | 1:15 to 1:18 |
| Cold brew (concentrate) | 1:5 | 1:4 to 1:8 |
The one worth memorising: 60 g of coffee per litre for anything filter, and 1:2 for espresso.
Where the ratio stops being the answer
- Espresso is measured on the way out, not on the way in. A ratio of 1:2 means 18 g of coffee producing 36 g of liquid in the cup, which is why a set of scales does more for espresso than any accessory sold alongside the machine.
- A moka pot fixes its own water: you fill to the safety valve and the basket holds what it holds. The dose is not really yours to choose, so grind and heat are the two things left to adjust.
- Cold brew is normally made as a concentrate and cut in the cup, often one part concentrate to two or three parts water or milk. A 1:5 recipe is not a drink until you dilute it.
- Bean-to-cup machines dose for you, usually between 7 and 14 g, and most of them let you raise it. If the coffee tastes thin, the dose setting is the first place to look — long before the beans get blamed.
Quick answers
How much coffee for one mug?
For a 250 ml mug at 1:16, about 15 g — a level, generously heaped tablespoon, though the tablespoon is exactly the imprecision the scales exist to remove.
How much coffee per litre?
Sixty grams, which is 1:16.6 and the figure most brewing guidance is built around. A full French press or a carafe brewer is the place this matters most, because the error scales with the volume.
Does the ratio change for dark roast?
The ratio holds; the grind and the water temperature are what move. Darker roasts are more soluble, so they extract faster and are easier to push into bitterness — a slightly coarser grind usually fixes that without touching the dose.
Is a scoop good enough?
For a while. A scoop varies by several grams depending on roast, grind and how it was filled, and that variance is bigger than the gap between a good cup and a mediocre one. Scales that read to 0.1 g cost less than a bag of good beans.
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