Coffee-to-Water Ratio Calculator
Enter how many cups you want to brew, pick your brewing method and preferred strength, and this calculator tells you exactly how much ground coffee and water to use in grams, millilitres, tablespoons and ounces. It also estimates your cost per cup if you enter the price of your bag of beans. Switch between metric and imperial at any time.
What is the golden coffee-to-water ratio?
The Specialty Coffee Association (SCA) defines the "Golden Cup Standard" as 55 g of coffee per litre of water, which works out to roughly a 1:18 ratio. Most specialty roasters recommend landing somewhere between 1:15 and 1:17 for filter-style brews, meaning 1 gram of ground coffee for every 15 to 17 grams (or millilitres) of water. The exact sweet spot varies by method, roast level, and personal taste: a coarser grind and a longer steep in a French press typically need a slightly stronger ratio (closer to 1:15) to compensate for less extraction efficiency, while a fine-grind method like espresso operates at a dramatically tighter ratio around 1:2.
How to measure coffee without a scale
A kitchen scale produces the most consistent cup because the weight of a tablespoon of ground coffee varies by grind size and roast. One level US tablespoon of medium-ground coffee weighs roughly 5 to 6 grams, so two tablespoons per 6-ounce (180 ml) serving is a reasonable starting point for drip coffee. For the most precise result always weigh your coffee and your water: a simple digital scale costs under $15 and removes the biggest source of inconsistency in home brewing. If a scale is unavailable, keep the tablespoon measure consistent and adjust incrementally, adding or removing half a tablespoon at a time, until the strength suits you.
Brewing method comparison: ratios and grind sizes
Different extraction methods require different ratios largely because of how long the water is in contact with the coffee grounds. Immersion methods such as French press and cold brew allow full contact throughout the brew, so they tolerate a slightly stronger ratio (less water per gram of coffee). Percolation methods such as pour over and auto-drip constantly expose fresh water to the grounds, enabling a more efficient extraction at a higher ratio (more water per gram). Espresso operates under pressure with very little water, producing a highly concentrated output that is typically diluted with hot water or milk. Cold brew concentrates at 1:8 or tighter and is often diluted 1:1 or 1:2 before drinking, making the effective drinking ratio closer to 1:16.
Cost per cup: why specialty coffee is cheaper than it looks
A bag of specialty whole-bean coffee often seems expensive compared to supermarket ground coffee, but the cost per cup is frequently lower than it appears. At a 1:16 ratio, a 250 g bag of coffee yields roughly 32 cups (about 7.8 g per cup). If that bag costs $16, the bean cost is roughly $0.50 per cup, far below a cafe price of $4 to $6. Buying in larger quantities and grinding fresh extends both the value and the flavour. The cost calculator above accounts for your bag weight and price so you can see exactly what each home-brewed cup costs.
Coffee-to-water ratio guide by brewing method
| Brewing method | Mild (1:X) | Medium (1:X) | Strong (1:X) | Grind size |
|---|---|---|---|---|
| Auto-drip / Filter | 18 | 16 | 14 | Medium |
| Pour Over (V60) | 18 | 16 | 14 | Medium-fine |
| French Press | 17 | 15 | 13 | Coarse |
| AeroPress | 16 | 14 | 12 | Medium to medium-fine |
| Chemex | 18 | 16 | 14 | Medium-coarse |
| Cold Brew | 10 | 8 | 6 | Coarse (steep 12-24 h) |
| Moka Pot | 10 | 8 | 6 | Fine (not espresso-fine) |
| Siphon / Vacuum Pot | 16 | 14 | 12 | Medium-fine |
| Espresso | 2.5 | 2 | 1.5 | Very fine (pressurised) |
Ratios are expressed as 1 part coffee to X parts water by weight. Adjust within each range to taste.
Frequently asked questions
How much coffee do I use per cup?
For a standard 237 ml (8 fl oz) cup using the widely recommended 1:16 ratio, you need about 15 g (roughly 2.5 tablespoons) of ground coffee. Adjust upward for a stronger brew or downward for a milder one. Espresso uses far less water: a double shot (60 ml) from 18 g of coffee gives a 1:3.3 ratio before any dilution.
Is it better to measure coffee by weight or by volume?
By weight. A tablespoon of finely ground coffee holds significantly more coffee than a tablespoon of coarsely ground coffee, so the same volume measure gives different results as grind size changes. A gram is always a gram, making weight the most reproducible approach, especially when you adjust grind size while dialling in a new bean.
What ratio should I use for cold brew?
Cold brew is typically brewed as a concentrate using a 1:8 ratio (1 g coffee per 8 ml water) and then diluted with water or milk before drinking at roughly 1:1 or 2:1. If you prefer to brew at drinking strength from the start, use a 1:12 to 1:16 ratio and steep for 12 to 24 hours in the refrigerator. Coarse grounds prevent over-extraction during the long cold steep.
How do I make my coffee stronger without using more grounds?
Grind finer (more surface area extracts faster), use hotter water (closer to 96 degrees C / 205 degrees F), extend brew time slightly, or reduce the amount of water while keeping the coffee the same. Brewing stronger than about 1:12 for filter methods often produces bitterness rather than more flavour, so adjusting grind size is usually the most effective lever.
What grind size should I use for each brewing method?
Coarse (like rough sea salt): French press, cold brew. Medium-coarse: Chemex. Medium: auto-drip, pour over. Medium-fine: AeroPress, siphon, V60. Fine: Moka pot. Very fine: espresso. The coarser the grind, the slower the extraction, which is why immersion methods that steep for several minutes need a coarser grind to avoid bitterness.