Coffee-to-Water Ratio Calculator
Coffee-to-water ratio calculator — pick a brew method or ratio and enter the water (or coffee) you want, and get the exact matching dose for a consistent cup every time. Covers pour-over, French press, AeroPress, cold brew and espresso. Runs in your browser.
Coffee-to-Water Ratio Calculator
How to Use the Coffee Ratio Calculator
Pick a method or ratio
Tap a brew method for its typical ratio, or set your own with the slider.
Choose what to fix
Start from the water you want to brew, or from a fixed amount of coffee.
Read the dose
Get the matching coffee and water, plus an approximate cup count.
Tune to taste
Lower the ratio number for a stronger cup, raise it for a lighter one.
The One Number That Fixes Home Coffee
If your coffee comes out differently every morning, the culprit is almost always inconsistent measuring, and the cure is a single number: the coffee-to-water ratio. Expressed as 1:N by weight, it says how many grams of water you use for each gram of ground coffee — so a ratio of 1:16 means 500 grams of water needs about 31 grams of coffee. That ratio is the master control of strength. Get it right and dialled in for your taste, and every brew lands in the same place; leave it to guesswork with a scoop and you are starting from scratch each time. This calculator lets you fix either the water or the coffee and instantly gives you the other to match your chosen ratio, along with a rough cup count.
Different brewing methods cluster around different ratios, which is why the tool offers presets. Filter and pour-over coffee lives around the widely-cited “golden ratio” of 1:16; AeroPress is typically a little stronger near 1:14; French press stronger still around 1:12; cold brew is made deliberately concentrated at roughly 1:8 and then diluted to taste; and espresso is in a different world entirely at about 1:2. The direction is intuitive once you see it: a smaller second number means less water per gram of coffee, and therefore a stronger, more intense cup. If a brew tastes thin and watery, lower the number; if it tastes harsh or overpowering, raise it. Adjustments of even a point or two are clearly noticeable.
The reason ratios are written by weight, and why this tool asks for grams, is consistency. A scoop measures volume, but ground coffee varies in density with the bean, the roast and the grind, so the same scoop can deliver quite different amounts of actual coffee. A kitchen scale removes that variable, and because water weighs almost exactly one gram per millilitre you can measure it by weight or volume interchangeably. Ratio is not the only thing that shapes a cup — grind size, water temperature and brew time all matter — but it sets the foundation of strength on which everything else builds, so nailing it first is the fastest route to better, repeatable coffee. Everything here is computed in your browser from the simple ratio arithmetic, so the recipe you settle on never leaves your device, and you can share it as a link.
Grind and temperature refine a cup, but the ratio sets its strength — weigh it once and your coffee stops being a lottery.
10 Facts About Brew Ratios
Coffee ratio is 1 part coffee to N parts water, by weight.
A “golden ratio” for filter coffee is around 1:16.
A lower N (e.g. 1:12) makes a stronger brew.
1 ml of water weighs about 1 gram.
French press is usually brewed stronger (~1:12).
Espresso runs very concentrated, around 1:2.
Cold brew is made strong (~1:8) then often diluted.
A kitchen scale beats scoops for consistency.
Grind size and time matter too, but ratio sets strength.
This calculator runs in your browser — nothing is uploaded.
Frequently Asked Questions
- It is the proportion of ground coffee to water, written as 1:N by weight — one part coffee to N parts water. A ratio of 1:16, for example, means sixteen grams of water for every gram of coffee, so 500 g of water needs about 31 g of coffee. It is the single biggest lever on how strong your brew tastes.
- It depends on the method and your taste. Filter and pour-over coffee is commonly around 1:16, AeroPress about 1:14, French press a touch stronger near 1:12, cold brew strong at roughly 1:8 (often then diluted), and espresso very concentrated at about 1:2. Pick the preset that matches your brewer and adjust from there.
- A lower second number makes a stronger brew, because there is less water per gram of coffee. So 1:12 is stronger than 1:16. If your coffee tastes weak or watery, lower the number; if it tastes harsh or too intense, raise it. Small changes make a noticeable difference.
- Scoops measure volume, and ground coffee varies in density with bean, roast and grind, so the same scoop can hold quite different amounts. Weighing the coffee and the water on a scale removes that variability and is what makes a brew repeatable cup after cup. It is the habit that most improves home coffee.
- Either, because water’s density is almost exactly one gram per millilitre, so 500 ml weighs about 500 g. A scale is most convenient since you can pour straight onto it, but a measuring jug works too. The calculator treats grams and millilitres of water as interchangeable.
- Yes. Switch the input mode to start from a fixed amount of coffee — say the 18 g your grinder is set for — and the tool gives the water to match your chosen ratio. It works in both directions so you can plan around whichever you want to fix.
- For the rough cup count, the tool uses 240 ml of water per cup, a common standard, so 480 g of water is about two cups. Mugs vary widely, so treat the cup figure as an approximate guide to batch size rather than an exact serving count.
- No — it sets the brewing ratio, not the final liquid in your cup. Coffee grounds soak up and retain some water, so the volume you drink is a little less than the water you added, especially in immersion methods. That is normal; the ratio still controls strength, which is what matters for taste.
- No, but it sets the strength, which is the foundation. Grind size, water temperature, brew time and the coffee itself all shape flavour and extraction on top of the ratio. Getting the ratio right first gives you a consistent base to then tune those other variables.
- Completely free, with no account or usage limit. It runs entirely in your browser, collects no data, and works offline once the page has loaded.
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