Coffee-to-Water Ratio Calculator
Dial in any brew by weight. Set your ratio, then start from whatever you know — the water you want to use, the number of cups, or a fixed dose of coffee — and get the exact grams of each.
Lower is stronger. Common: 1:15–1:18 for drip and pour-over, 1:12–1:15 for French press.
1 g of water = 1 mL.
Formula & how it works
With a ratio of 1:R, coffee = water ÷ R and water = coffee × R. Starting from cups, water is cups × cup size converted to grams (1 fl oz ≈ 29.57 mL, and 1 mL of water ≈ 1 g).
Worked example
At a 1:16 ratio with 500 g of water, coffee is 500 ÷ 16 = 31 g. That water fills roughly 2.8 six-ounce cups. Prefer to fix the dose? Thirty grams of coffee at 1:16 calls for 480 g of water.
Brewing by ratio
Why weight beats scoops
A tablespoon of light-roast beans weighs differently from the same scoop of oily dark roast, and grind size changes how grounds pack. Weighing coffee and water in grams removes that variability, so a recipe you like is one you can repeat exactly tomorrow.
Choosing your number
Ratio is the main strength dial. Around 1:16 is a balanced everyday cup; drop toward 1:14 for a bolder brew or push to 1:18 for something lighter and more tea-like. Brew method matters too — immersion methods like French press often run a little stronger than drip.
Scaling up cleanly
Because the ratio is fixed, scaling from one cup to a full carafe is just multiplication. Start from the cup count for a gathering, or from a water amount if you are filling a specific kettle or server, and the coffee scales right along with it.