Coffee Grounds (I know how much coffee I have)
Water Amount (I know how much I want to drink)
— Choose a Method —
Pour Over / Drip (1:15 – Strong)
Pour Over / Drip (1:16 – Balanced)
Pour Over / Drip (1:17 – Mellow)
French Press (1:12 – Rich)
Espresso (1:2 – Standard)
Cold Brew (1:8 – Concentrate)
Your Brewing Recipe
Coffee: 0 g
Water: 0 ml (g)
Note: 1ml of water equals 1 gram.
Mastering the Coffee to Water Ratio
The secret to a barista-quality cup of coffee isn't just the beans; it's the coffee to water ratio. This ratio determines the strength and extraction level of your brew. Whether you are using a Chemex, a French Press, or a standard drip machine, getting the math right is the first step toward consistency.
Why Does the Ratio Matter?
Coffee brewing is a chemical process of extraction. If you use too much water, you over-extract the grounds, leading to a bitter, hollow taste. If you use too little water, you under-extract, resulting in a sour, salty, or overly concentrated flavor. The "Golden Ratio" is generally considered to be 1:15 to 1:18.
Standard Ratios by Brewing Method
Method
Ratio Range
Description
Pour Over
1:15 – 1:17
Clean, bright, and highlights flavor notes.
French Press
1:12 – 1:15
Full-bodied, rich, and textured.
Drip Machine
1:16 – 1:17
Consistent, standard everyday strength.
Espresso
1:1.5 – 1:2.5
Highly concentrated and intense.
Cold Brew
1:4 – 1:8
Often brewed as a concentrate to be diluted later.
How to Use This Calculator
Choose your mode: Decide if you want to find out how much water to use for the coffee you have, or how much coffee you need for a specific mug size (e.g., 300ml).
Enter your values: Input your grams of coffee or milliliters of water.
Set your ratio: Use a preset for your brewing method or customize it (1:16 is a great starting point for most).
Brew: Use a digital scale for the most accurate results. Measuring by volume (scoops and cups) is often inaccurate because different beans have different densities.
Example Calculation
If you have 20 grams of coffee and want a 1:16 ratio:
Calculation: 20g × 16 = 320ml of water.
If you want to fill a 500ml thermos using a 1:15 ratio:
Calculation: 500ml ÷ 15 = 33.3g of coffee.
function toggleInputs() {
var mode = document.getElementById("calcMode").value;
var label = document.getElementById("inputLabel");
var mainInput = document.getElementById("mainInput");
if (mode === "coffee") {
label.innerHTML = "Coffee (grams)";
mainInput.placeholder = "e.g. 20";
} else {
label.innerHTML = "Water (ml)";
mainInput.placeholder = "e.g. 300";
}
}
function applyPreset() {
var preset = document.getElementById("presetRatios").value;
if (preset) {
document.getElementById("ratioInput").value = preset;
}
}
function calculateCoffee() {
var mode = document.getElementById("calcMode").value;
var inputValue = parseFloat(document.getElementById("mainInput").value);
var ratio = parseFloat(document.getElementById("ratioInput").value);
var resCoffeeDisplay = document.getElementById("resCoffee");
var resWaterDisplay = document.getElementById("resWater");
var resultsDiv = document.getElementById("coffeeResults");
if (isNaN(inputValue) || isNaN(ratio) || inputValue <= 0 || ratio <= 0) {
alert("Please enter valid positive numbers for both fields.");
return;
}
var coffeeResult, waterResult;
if (mode === "coffee") {
// Input is coffee, find water
coffeeResult = inputValue;
waterResult = inputValue * ratio;
} else {
// Input is water, find coffee
waterResult = inputValue;
coffeeResult = inputValue / ratio;
}
resCoffeeDisplay.innerHTML = coffeeResult.toFixed(1);
resWaterDisplay.innerHTML = Math.round(waterResult);
resultsDiv.style.display = "block";
}