Coffee to Water Ratio Calculator
A brew ratio is millilitres of water per gram of coffee. Around 1:15 is the common starting point, and a smaller second number means a stronger cup. Water weighs almost exactly what it measures, so one scale does both jobs.
Your numbers
Water to pour
300mL
Volume (mL)
260mL
Formula
Water to pour = Coffee × Water ratio
Not all the water reaches the cup. The grounds hold back roughly 2 mL per gram, so 20 g brewed with 300 mL yields about 260 mL.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Coffee (g)The weight of coffee, measured before grinding. | 20 | 0 and up |
| Water ratio (×)Millilitres of water per gram of coffee; smaller means stronger. | 15 | 0 and up |
Step by step
Quick reference table
Results when only Coffee (g) changes and everything else stays put.
| Coffee (g) | Water to pour (mL) | Volume (mL) (mL) |
|---|---|---|
| 10 | 150 | 130 |
| 15 | 225 | 195 |
| 20 | 300 | 260 |
| 30 | 450 | 390 |
| 40 | 600 | 520 |
What each result means
| Result | At default values |
|---|---|
| Water to pour (mL)The water you pour in — more than what ends up in the cup. | 300 |
| Volume (mL) (mL)Volume in millilitres. | 260 |
Common mistakes
Not all the water reaches the cup. The grounds hold back roughly 2 mL per gram, so 20 g brewed with 300 mL yields about 260 mL.
Glossary
- Coffee
- The weight of coffee, measured before grinding.
- Water ratio
- Millilitres of water per gram of coffee; smaller means stronger.
- Water to pour
- The water you pour in — more than what ends up in the cup.
- Volume (mL)
- Volume in millilitres.
Frequently asked questions
Q. How is Coffee to Water Ratio Calculator calculated?
Water to pour = Coffee × Water ratio — A brew ratio is millilitres of water per gram of coffee. Around 1:15 is the common starting point, and a smaller second number means a stronger cup. Water weighs almost exactly what it measures, so one scale does both jobs.
Q. Can you walk through an example?
With Coffee 20g, Water ratio 15×, the answer is Water to pour 300mL.
Q. What do I need to enter?
Enter Coffee, Water ratio. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Coffee (g) moves the answer to Coffee (g) 10 → Water to pour (mL) 150 and Coffee (g) 40 → Water to pour (mL) 600. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
Not all the water reaches the cup. The grounds hold back roughly 2 mL per gram, so 20 g brewed with 300 mL yields about 260 mL.
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