The ratio of coffee to water is the single biggest factor you control when brewing at home. Too little coffee and the cup tastes thin; too much and it turns heavy and harsh. Measuring by weight makes it easy to repeat a cup you like.
What the ratio means
A ratio of 1:16 means 1 gram of coffee for every 16 grams of water. Because 1 millilitre of water weighs about 1 gram, you can read grams of water and millilitres as the same number.
Coffee (g) = Water (g or ml) ÷ Ratio
Common starting ratios
- 1:15: stronger, fuller cup.
- 1:16: a balanced middle ground that many home brewers start with.
- 1:17 to 1:18: lighter and brighter. The Specialty Coffee Association’s brewing guidance for drip coffee centres on about 55 grams per litre, roughly 1:18.
Quick dose table
| Water | 1:15 | 1:16 | 1:17 |
|---|---|---|---|
| 250 ml | 16.7 g | 15.6 g | 14.7 g |
| 350 ml | 23.3 g | 21.9 g | 20.6 g |
| 500 ml | 33.3 g | 31.3 g | 29.4 g |
| 1,000 ml | 66.7 g | 62.5 g | 58.8 g |
Worked example
You want a 500 ml pour-over at 1:16: 500 ÷ 16 = 31.25 g of coffee. Weigh the beans, grind, then pour 500 g of water over the grounds.
Why your cup is smaller than the water you poured
Coffee grounds hold on to some water. A commonly used estimate is about 2 grams of water per gram of coffee, so 31 g of coffee keeps around 60 ml and you end up with roughly 440 ml in the cup.
Fixing taste problems
| Taste | Try this first |
|---|---|
| Weak or watery | Use more coffee (for example move from 1:17 to 1:16) |
| Too strong or heavy | Use less coffee or more water |
| Sour or sharp | Grind a little finer or brew slightly longer |
| Bitter or dry | Grind a little coarser or brew slightly shorter |
Change one thing at a time so you know what made the difference.
Why weigh instead of using scoops?
A scoop of coffee can weigh noticeably different amounts depending on the roast and grind. A cheap kitchen scale removes that guesswork.
Calculate your dose
The coffee to water ratio calculator gives the exact grams for any cup size and ratio. For caffeine estimates, use the coffee calculator.
Frequently asked questions
There is no single best ratio; 1:15 to 1:18 covers most tastes. Many people start at 1:16 and adjust.
For a 250 ml cup at 1:16, about 15.6 g of coffee.
The term usually refers to brewing guidance of about 55 grams of coffee per litre of water, around 1:18.
Methods vary. French press is often brewed around 1:15 to 1:16, while cold brew concentrate uses much stronger ratios before being diluted.
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