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.
- How strong that is
- 1:16 is in the middle of the usual range for brewed coffee.
- To change the strength
- For a stronger cup, lower the second number. At 1:15, use 225 g of water for the same 15 g of coffee. That is more coffee for each gram of water.
- For a weaker cup, raise the second number. At 1:17, use 255 g of water for the same 15 g of coffee. That is less coffee for each gram of water.
- When the ratio is the wrong thing to change
- Change the ratio when the flavour is right and the cup is simply too intense or too thin. If it tastes sour or sharp, or bitter and drying, that is extraction, not strength: keep the ratio and change the grind. Change one of the two at a time.
- What this cannot tell you
- The arithmetic is exact. Whether this ratio suits your coffee is a matter of taste, and the bands describe common practice, not a correct answer. The grounds also hold back roughly twice their weight in water, so the cup is smaller than the water you pour.
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.
What to do with the result
- You are making more or fewer cups than the recipe was written for: Brew recipe scaler
- You want your brewer's own starting recipe to set these amounts beside: Brewing methods: a starting point for each brewer
- It is a pour-over and you want the amounts as a pouring schedule: Pour-over planner
- The strength is right and the cup still tastes wrong: Make my coffee better
- You want to know why strength and extraction are two different numbers: Extraction basics: two numbers
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.
Assuming a bitter cup can only be fixed at the grinder
In the one trained-panel study read, bitterness rose with the strength of the brew and showed no significant link to extraction. A slightly weaker ratio is a fair first test for a bitter cup; if it only turns thin, go back and change the grind instead.
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.
Where to go next
Learn the technique
Background reading
Equipment involved
Drinks and methods
Other tools
Practise this in a lesson
Become a Barista · Level 1
The task: Enter the dose and water you used for your last brew, then ask for the same drink one step stronger. Note whether the calculator changes the coffee or the water, and work out which you would rather change.