Coffee Ratio Calculator
Calculate brew water from coffee dose using ratios from 1:12 (strong) to 1:18 (light). Useful for V60, AeroPress, French press and pour-over coffee brewing.
Last updated: May 2026
Enter coffee dose to calculate water amount.
Coffee brewing ratios explained
The ratio controls extraction: more water dilutes the cup, less water concentrates it. A 1:15 ratio (1g coffee per 15g water) gives a strong, dense brew; 1:18 produces a lighter, more transparent cup. Most specialty coffee recipes sit between 1:15 and 1:17 depending on the roast level and brewing method.
Ratios by brew method
- Pour-over (V60, Chemex): 1:15 to 1:17
- AeroPress: 1:12 to 1:15 for concentrate, 1:16 for regular
- French press: 1:15 to 1:17 with a 4-minute steep
- Espresso: 1:2 to 1:2.5 (18g in, 36 to 45g out)
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Frequently Asked Questions
Why does espresso use tighter ratios than pour-over coffee?
Espresso forces water through coffee under pressure, creating a more efficient extraction in seconds. That means less water is needed per gram of coffee to pull balanced flavor. Pour-over relies on contact time and gravity, so it needs more water to fully extract the solids. A 1:2 espresso ratio (like 18g coffee to 36g water) would produce a thin, under-extracted shot, but a 1:16 pour-over ratio (18g to 288g) gives the right body and sweetness for that method.
What happens if you use the wrong ratio?
Too much water produces over-extracted coffee: bitter, astringent, thin-bodied, sometimes with a grainy texture. Too little water leaves the coffee sour and thin because you haven't dissolved enough of the soluble solids. The ratio controls how much of the coffee's flavor compounds end up in the cup. Professional espresso machines measure this obsessively because off-ratio shots are obvious to anyone who tastes them—baristas use scales to dial in exact grams before every shift.
Can I use the same ratio for different grind sizes?
A finer grind needs slightly less water because it has more surface area, so extraction happens faster. A coarser grind needs more time and often slightly more water to fully extract. The 1:15–1:18 range works for espresso at standard grind, but if you grind finer for a lever machine or coarser for a full-immersion brewer like a French press, you may need to adjust the ratio by a few percentage points. Many brewers adjust ratio by feel once they understand how their specific equipment and coffee beans behave.
Why do coffee roasters recommend different brewing ratios?
Lighter roasts have denser, tighter cell structure, so they need slightly more contact time and sometimes a bit more water to fully extract the subtle flavors. Darker roasts are already partially "cooked," so they extract quickly and can get over-extracted if water contact is too long. A light roast might brew beautifully at 1:17, while the same roaster's dark roast sings at 1:15. The roaster's instructions reflect their target cup profile for that specific bean.
Does water temperature affect the brewing ratio?
Hotter water extracts faster and more aggressively, so you might use a tighter ratio (less water) or shorter contact time. Cooler water (under 90°C) extracts slower, so you need more contact time or slightly more water to pull the same flavor. This is why cold brew coffee uses a much looser ratio (like 1:4 or even 1:8) but steeps for 12+ hours instead. The ratio and brew time are linked—hotter and faster go together, cooler and slower go together.