Coffee to Water Ratio Calculator
This calculator works out the exact coffee to water ratio for any brew method, so you get consistent, well-balanced coffee every time instead of guessing with a scoop or spoon. Choose which direction you want to calculate: enter your coffee dose in grams to find the water needed, or enter a water volume in millilitres to find the coffee dose required. Set the number of cups you are brewing, then pick a ratio preset for your method, espresso at 1:2, cold brew at 1:8, moka pot at 1:10, French press at 1:15, pour over at 1:16 or 1:17, or the Specialty Coffee Association golden ratio at 1:18, or enter your own custom ratio. The calculator returns your coffee dose, the water needed, the ratio used, and the approximate brewed yield after the grounds absorb some water. Below that sits a ratio comparison table showing coffee and water amounts across all the common ratios for your chosen cup size, plus a full breakdown of your brew and a scaling guide for making one, two, four or eight cups, or a full litre. Because water weighs one gram per millilitre, millilitres and grams are interchangeable throughout. Weigh your coffee and water on a digital scale rather than measuring by volume for the most reliable results, and adjust the ratio up for a lighter cup or down for a stronger one.
1. Your Coffee
2. Brew Ratio
Ratio Comparison Table
| Ratio | Brew Style | Coffee (g) per cup | Water (mL) per cup | Strength |
|---|
Your Brew Breakdown
Scaling Guide
How the Coffee to Water Ratio Works
The coffee to water ratio is the single most important variable in brewing flavourful coffee. It is expressed as a ratio of coffee to water by weight, most commonly as 1:X where X is the number of grams of water for every gram of coffee. Because water weighs exactly 1 gram per millilitre at room temperature, the ratio works equally well using millilitres for water.
The formula is straightforward:
- Water (mL) = Coffee (g) x Ratio
- Coffee (g) = Water (mL) / Ratio
For example, with 18 g of coffee at a 1:16 ratio: Water = 18 x 16 = 288 mL.
SCA Golden Ratio and Recommended Ranges
The Specialty Coffee Association (SCA) recommends a brewing ratio of 55 grams of coffee per litre of water (1:18.2) as its "golden cup standard." In practice, most specialty coffee drinkers use ratios between 1:15 and 1:18. A lower ratio number (such as 1:12) produces a stronger, more concentrated brew. A higher ratio number (such as 1:18) produces a lighter, more delicate cup.
Ratios by Brew Method
| Brew Method | Typical Ratio | Coffee per 250 mL | Notes |
|---|---|---|---|
| Espresso | 1:2 | 25 g (for 50 mL yield) | Highly concentrated; usually 18-20 g in, 36-40 mL out |
| Moka pot | 1:7 to 1:10 | 25-35 g | Use finely ground coffee; fill basket fully |
| AeroPress | 1:6 to 1:15 | 16-40 g | Flexible; concentrate or full cup both common |
| French press | 1:12 to 1:16 | 15-20 g | Coarse grind; 4-minute steep |
| Pour over (V60, Chemex) | 1:15 to 1:17 | 14-16 g | Medium-fine grind; 3 to 4 minute brew |
| Filter / drip machine | 1:16 to 1:18 | 13-15 g | Medium grind |
| Cold brew | 1:7 to 1:10 | 25-35 g | Coarse grind; steep 12-24 hours; dilute before drinking |
Worked Example
You want to make one 250 mL cup of pour over coffee at a 1:16 ratio:
- Coffee dose = 250 mL / 16 = 15.6 g (round to 15 or 16 g)
- Water needed = 15.6 g x 16 = 250 mL
- Set your kettle to 92-96 degC and pour slowly in stages over 3 minutes
The calculator uses 18 g coffee as the default (common single-serve pour over dose). At 1:16, that requires 18 x 16 = 288 mL of water and produces approximately 250-270 mL of brewed coffee (some water is absorbed by the grounds).
Tips for Consistency
- Always weigh your coffee and water in grams rather than using volume spoons. Ground coffee density varies significantly by roast and grind, so tablespoons are unreliable.
- A digital scale with 0.1 g precision is the most important piece of brewing equipment after the grinder.
- Water quality matters. Use filtered water. Mineral content (especially magnesium and calcium) affects extraction. Aim for water in the 75-250 ppm total dissolved solids range.
- Water temperature for most methods should be 90-96 degC. Cooler water (around 85 degC) suits lighter roasts; hotter water suits darker roasts.
- Grind size affects extraction speed. If your coffee is too bitter, grind coarser or reduce the ratio. If it is too sour or weak, grind finer or increase the coffee dose.
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Method: Water (mL) = Coffee (g) x Ratio; Coffee (g) = Water (mL) / Ratio. Water density taken as 1.000 g/mL at room temperature. Ratio presets based on Specialty Coffee Association brewing standards and widely published brew guides.
Ratios and brew parameters shown are general guidance based on widely accepted specialty coffee standards. Actual results depend on your specific coffee, grinder, water quality, and brew technique. Adjust to your taste.