Tool
Coffee ratio and strength calculator
Three directions: water from a dose, dose from a water amount, or the actual ratio of a brew you have already made.
Water needed
240 g
That is 1:16 — 62.5 g of coffee per litre of water, which is how brewing-method pages here express it.
How this was worked out
Water = coffee dose × ratio
15 × 16 = 240 g
Water is treated as 1 g per ml, which is close enough for brewing.
Exact arithmetic on your numbers
If you have no scale
A level tablespoon of ground coffee is commonly somewhere around 5 to 7 g, and the spread is real rather than cautious: it moves with grind size, roast level and how the spoon was filled, and a coarse grind can be a third lighter than a fine one for the same spoon. Use it to get in the region, expect to be several grams out, and treat a scale as the single cheapest thing that makes a brew repeatable.
How it works
A brew ratio is one number divided by another. Water is the dose multiplied by the ratio; dose is the water divided by the ratio; and if you know both, the ratio is the water divided by the dose. The same arithmetic is also shown as grams of coffee per litre, which is how brewing standards usually express it and how most brewing-method records here are written.
What the inputs mean
- Coffee dose
- The dry ground coffee you put in, weighed before any water touches it.
- Water
- The total water you pour through or steep the coffee in — not what ends up in the cup, which is always less because the grounds retain some.
- Ratio
- Written 1:16, meaning one part coffee to sixteen parts water by weight. A larger second number means a weaker brew.
Worked examples
A single V60 with a 15 g dose
- Coffee dose 15 g
- Ratio 1:16
Result: 240 g of water, which is 62.5 g of coffee per litre.
A common single-cup starting point rather than a rule.
A litre of batch filter
- Water 1,000 g
- Ratio 1:16.7
Result: 60 g of coffee, which is 60 g per litre.
Checking a brew that tasted good
- Coffee dose 22 g
- Water 350 g
Result: 1:15.9 — worth writing down so it can be repeated.
Common mistakes
Measuring the coffee in the cup rather than the water poured in
The grounds hold back a meaningful amount of water, so beverage weight is always lower than brew water. Using it as the ratio's second number makes every brew look stronger than it was.
Using a filter ratio for espresso
Espresso is measured dose-to-yield, not dose-to-brew-water, and the two numbers are not comparable. Use the espresso ratio calculator instead.
Changing the ratio to fix bitterness
Bitterness is usually over-extraction, which is a grind and contact-time problem. A weaker ratio makes a bitter brew taste like a thin bitter brew.
What the result does not mean
- A brew ratio is not the same as measured beverage strength. Strength as brewers mean it is dissolved solids in the finished cup, which depends on how much of the coffee actually extracted, not only on how much coffee went in.
- Two brews at the same ratio can taste completely different if the grind or the water temperature differs.
What this does not account for
- Uses a linear ratio and does not model diminishing returns at very high or very low ratios.
- Water is treated as 1 g per ml, which is close enough for brewing and not exactly true at brewing temperature.
- Does not account for grind size, water temperature or brew time — the ratio is one variable among several.