Coffee to Water Ratio Calculator
Enter how much coffee or water you have, choose your brew method and strength, and get the exact amounts you need. Works in grams, millilitres, tablespoons, and fluid ounces. Supports 8 brew methods with grind size and water temperature guidance included.
The coffee to water ratio: why it matters
The ratio of ground coffee to water is the single biggest variable you control in brewing. Too little coffee and the water over-extracts, pulling bitter, harsh flavors. Too much coffee and it under-extracts, leaving a sour, weak cup. The Specialty Coffee Association (SCA) defines the "golden ratio" for drip brewing as roughly 55 g per litre (about 1:16 to 1:18 water-to-coffee by weight). Every other brew method adapts this principle to its unique contact time and pressure, which is why a French press uses a different ratio than an espresso machine.
How to use this calculator
Pick whether you know your water volume, your coffee amount, or the number of cups you want to make. Select your brew method and preferred strength, then switch between metric (grams and millilitres) and imperial (ounces and fluid ounces) as needed. The calculator returns the coffee and water amounts, the exact ratio, an approximate tablespoon count, the recommended grind size, water temperature, and typical brew time for your chosen method. The chart at the bottom shows how much coffee you would need for 1 to 8 cups at your chosen ratio, so you can scale up or down without recalculating.
Grams vs tablespoons: which to use
Weighing in grams is far more consistent than measuring by volume. Ground coffee density varies widely between grind sizes, roast levels, and bean types: a tablespoon of finely ground espresso can weigh 7 g while the same tablespoon of coarse cold-brew grind may weigh only 4 g. Scales take the guesswork out completely. If you only have a tablespoon measure, use the tablespoon output as a guide, but know that 1 level tablespoon of ground coffee is approximately 5-6 g for medium grinds. A kitchen scale costs very little and makes a noticeable difference in cup consistency.
Scaling up: brewing for a crowd
The ratio stays constant no matter how many cups you make. For 4 cups (960 ml) at a 1:16 ratio you need 60 g of coffee. For 8 cups (1,920 ml) you need 120 g. Use the "number of cups" mode to scale any recipe automatically. One practical note: auto-drip machines and percolators often lose some water to steam before it reaches the grounds, so you may need to add an extra 10-15 ml per cup to compensate. Taste the result and adjust by a few grams at a time.
Recommended water-to-coffee ratios by brew method
| Brew method | Light | Regular | Strong | Grind size | Temp (degC) |
|---|---|---|---|---|---|
| Drip / Auto-drip | 1:17 | 1:16 | 1:15 | Medium | 91-96 |
| Pour-over / V60 | 1:17 | 1:15 | 1:14 | Medium-fine | 90-96 |
| Chemex | 1:17 | 1:16 | 1:15 | Medium-coarse | 91-96 |
| French Press | 1:16 | 1:15 | 1:13 | Coarse | 93-96 |
| AeroPress | 1:12 | 1:10 | 1:8 | Fine to medium | 80-90 |
| Moka Pot | 1:11 | 1:10 | 1:9 | Fine | 90-96 |
| Cold Brew | 1:7 | 1:6 | 1:5 | Extra coarse | Cold water |
| Espresso | 1:2.5 | 1:2 | 1:1.75 | Very fine | 90-96 |
Starting ratios from the Specialty Coffee Association and common barista guides. Adjust by one step at a time to find your preferred strength.
Frequently asked questions
What is the golden ratio for coffee?
The Specialty Coffee Association defines the golden ratio as approximately 1 gram of coffee per 16-18 grams of water (1:16 to 1:18). This translates to about 55-60 g of coffee per litre of water. It is a starting point, not a rule: adjust to your taste and brew method.
Why does each brew method use a different ratio?
Extraction efficiency depends on contact time, pressure, temperature, and whether the water is draining through or sitting with the grounds. Espresso extracts in 25-30 seconds under 9 bars of pressure, so it needs a very low ratio (1:2). Cold brew steeps for 12-24 hours with no heat, so it also uses a low ratio but as a concentrate you then dilute. French press steeps for 4 minutes with full immersion, which is efficient enough to use a moderate ratio around 1:15.
How many tablespoons of coffee per cup?
For a standard 240 ml cup at a 1:16 ratio, you need about 15 g of coffee, which is roughly 2 to 2.5 level tablespoons of medium-ground coffee. However, tablespoon volume is an approximation: grind size and roast level change the weight per spoon significantly. Weighing in grams gives more consistent results.
What water temperature should I use?
Most hot-brew methods work best between 90 and 96 degrees Celsius (195-205 degrees Fahrenheit). Below 90 C the water under-extracts and the cup tastes sour or flat. Above 96 C you risk scorching the grounds and pulling bitter compounds. AeroPress is an exception: many recipes use cooler water around 80-85 C to produce a smoother cup. Cold brew uses room-temperature or refrigerator-cold water, relying on time rather than heat for extraction.
Can I use this calculator for cold brew concentrate?
Yes. Select "Cold Brew" and choose "Very strong" for a concentrate (roughly 1:4 to 1:5) that you then dilute about 1:1 with water or milk before drinking. For regular-strength cold brew ready to drink straight, use "Regular" (around 1:6). Cold brew concentrate keeps refrigerated for up to 2 weeks, making it efficient to batch-brew.
Why does AeroPress use such a low ratio compared with drip coffee?
AeroPress ratios shown here are for the standard recipe, which produces a concentrate you then top up with water to taste. Many baristas brew AeroPress at 1:10 and add hot water to reach a final cup of roughly 1:16. If you prefer to brew directly to drinking strength, adjust the ratio upward toward 1:14 to 1:16 in the calculator.