How this instrument works
Coffee-to-water ratio is the single biggest lever on brew strength, and it isn't the same across brewing methods — a ratio that tastes balanced in a French press would taste thin through an espresso machine, and vice versa. Specialty coffee guidance generally centers on a 15-to-18-to-1 water-to-coffee range by weight for most immersion and drip-style methods, with espresso sitting in a completely different, much more concentrated range.
This calculator covers five common methods, each with its own typical ratio: drip/auto-drip around 1:16, pour-over around 1:17 (a commonly used specialty-coffee reference point), French press around 1:15, Moka pot around 1:10, and espresso around 1:2. Enter your coffee dose in grams, pick the method you're brewing, and the water amount adjusts to match — these are solid starting ratios, and like any recipe, worth nudging slightly to match your own taste and equipment.
- Enter how many grams of coffee you're using.
- Select your brew method from the list.
- Read off the water amount in milliliters for that method's ratio.
- Weigh both coffee and water on a scale for the most consistent results.
18g of coffee for pour-over
18 grams of coffee brewed pour-over at the roughly 1:17 ratio needs 18 x 17 = 306 mL of water — a common single-cup pour-over dose, sized for a standard mug plus a bit extra to account for water absorbed by the grounds.
The same 18 grams brewed as espresso instead, at roughly 1:2, would need only 18 x 2 = 36 mL of water — a fraction of the pour-over volume, reflecting how much more concentrated an espresso shot is compared to a filter-brewed cup.
Questions
Why do brewing methods use such different ratios?
Each method controls strength through a different mechanism, so the ratio that works for one doesn't transfer to another. Espresso forces hot water through finely packed grounds under pressure in under a minute, extracting a lot of flavor from very little water — hence its concentrated roughly 1:2 ratio. Drip and pour-over let water pass through coarser grounds once under gravity, needing more water relative to coffee to extract a similar depth of flavor, which is why their ratios sit closer to 1:15-1:17.
Should I measure coffee and water by weight or volume?
By weight, if you want the ratio to actually be accurate — a gram is a fixed amount of mass, while a 'cup' or 'scoop' of coffee varies with grind size and how tightly it's packed, and water's volume-to-mass relationship is close enough to 1:1 (1 mL ≈ 1 g) that measuring both on a kitchen scale in grams keeps the whole ratio consistent. This calculator's water output in milliliters assumes that near-1:1 relationship for water specifically.
Why is pour-over's ratio around 1:17 specifically?
A 1:17 water-to-coffee ratio by weight is a commonly used reference point in specialty coffee brewing guidance, sitting within the broader roughly 15-to-18-to-1 range considered balanced for filter-style methods. It's a starting point rather than a rigid rule — some brewers prefer slightly stronger around 1:15, others slightly more diluted around 1:18, and personal taste, bean freshness, and grind size all nudge the ideal ratio in practice.
Can I use this ratio with any grind size?
The ratio controls strength, but grind size controls extraction — how much flavor comes out of the coffee during the brew time — and the two need to match your method for good results. A too-fine grind for a long-contact method like French press can over-extract and taste bitter even at the right ratio, while a too-coarse grind for pour-over can under-extract and taste weak. Get the ratio right first, then dial in grind size to taste.