Ratio is the single biggest lever on how your coffee tastes, and it's the one most people never touch. Get it right and mediocre beans taste good. Get it wrong and the best beans in the world taste like disappointment.
The ratios
| Method | Ratio | Per 500 ml water |
|---|---|---|
| Drip / filter machine | 1:16 – 1:17 | 29–31 g |
| Pour over (V60, Chemex) | 1:16 | 31 g |
| French press | 1:15 | 33 g |
| AeroPress | 1:12 – 1:15 | 33–42 g |
| Cold brew concentrate | 1:5 – 1:8 | 63–100 g |
| Espresso | 1:2 | n/a — 18 g in, 36 g out |
Our coffee ratio calculator takes your water amount and strength and gives the coffee weight in grams.
Weigh it. Don't scoop it.
This is the highest-impact change most people can make, and it costs about the price of two bags of beans.
A tablespoon of coffee is a wildly unreliable unit. Grind size changes it — a fine grind packs denser than a coarse one, so the same scoop can vary by 30% or more. Bean density varies by roast level too; light roasts are denser than dark. Two scoops today and two scoops tomorrow are not the same amount of coffee.
Water is easy: 1 ml = 1 g, so a scale handles both sides of the ratio. A cheap kitchen scale that reads to 0.1 g does more for your coffee than any grinder upgrade under $200.
Ratio isn't the same as extraction
Worth separating, because they get conflated constantly.
Ratio controls strength — how much dissolved coffee is in your cup. Grind size and time control extraction — which compounds come out of the grounds.
That distinction diagnoses most bad coffee:
Bitter, harsh, dry finish → over-extracted. Grind coarser or brew shorter. Adding water won't fix it; you'll just have weak bitter coffee.
Sour, thin, salty → under-extracted. Grind finer or brew longer. Adding more coffee won't fix it either — you'll have strong sour coffee.
Tastes fine but weak/overpowering → that's ratio. Adjust it.
If your coffee is both bitter and sour, that's usually uneven extraction — often a grinder producing too many fines, or a pour that channelled.
Why espresso looks so different
Espresso's 1:2 isn't a stronger version of the same idea — it's a different process. Nine bars of pressure through a compacted puck in 25–30 seconds extracts far more, far faster, than gravity through a filter over four minutes.
The convention is 18 g in, 36 g out, in about 25–30 seconds. Note that's measured by output weight, not volume — crema makes volume useless as a measure. Chasing a specific number in the cup rather than a time on the clock is what separates consistent espresso from luck.
Dialling in your own
Start at 1:16 and change one variable at a time. Brew, taste, adjust. If you change grind and ratio together you learn nothing.
Then adjust to taste, honestly. Some people like 1:14. Some like 1:18. The ratios above are starting points refined by a lot of people over a long time, not laws — the cup you enjoy is the correct cup.
Filtered water — coffee is about 98% water. Heavily chlorinated tap water tastes like chlorinated coffee, and no ratio rescues it.
Try the free calculator
Skip the manual math — get instant numbers for your own project:
Frequently Asked Questions
What is the best coffee-to-water ratio?
Start at 1:16 — one gram of coffee to sixteen grams of water, or about 60 g per litre. French press suits 1:15 and espresso is roughly 1:2.
How much coffee per cup?
Around 31 g of coffee per 500 ml of water at a 1:16 ratio. Note that a coffee maker's 'cup' is usually 5 oz, not a full mug, which is why machine markings produce weak coffee.
Should I weigh coffee or use a scoop?
Weigh it. Scoop volume varies with grind size and roast level by up to 30%, so the same scoop rarely holds the same amount of coffee twice.
Why is my coffee bitter?
Usually over-extraction rather than too much coffee. Grind coarser or brew for less time — adding water only gives you weak bitter coffee.