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French Press Coffee Ratio Calculator

Calculate the coffee and water amounts for a French press based on your desired strength.

Result

Coffee Needed
47g

French press uses a coarser grind and longer steep time (typically 4 minutes) than drip coffee, and its ratio is conventionally expressed as water:coffee rather than coffee:water - this uses standard specialty coffee ratio ranges (1:17 light to 1:12 strong).

About the French Press Ratio

The French Press Coffee Ratio Calculator works out how many grams of ground coffee to use for a given amount of water, based on a chosen brew strength. It converts your water volume from ounces to grams and applies a standard specialty-coffee ratio so you can measure by weight rather than guessing at scoops.

How It Works

You enter your water volume in ounces and select a strength setting: light (1:17), medium (1:15), or strong (1:12), where these ratios describe parts water to one part coffee. The calculator converts the water volume to grams, then divides that figure by the ratio number for your selected strength to return the coffee weight needed.

Water (g) = water (oz) x 29.57. Coffee needed (g) = water (g) / ratio, where ratio is 17 for light, 15 for medium, and 12 for strong.

Formula & Methodology

French press ratios are conventionally written water-to-coffee rather than coffee-to-water, so a 1:15 medium ratio means 15 grams of water for every 1 gram of coffee. After converting your entered water volume from fluid ounces to grams using the standard 29.57 grams per ounce conversion, dividing by the ratio number isolates the coffee weight, since water grams divided by ratio equals coffee grams when 1 part coffee corresponds to that many parts water.

Examples

Medium-Strength 24oz Brew

With 24 oz of water at the medium (1:15) setting, the water converts to about 709.7g, giving a coffee amount of roughly 47g.

A Stronger Small Batch

With 12 oz of water at the strong (1:12) setting, the water converts to about 354.8g, giving a coffee amount of roughly 30g.

Advantages

  • Converts between fluid ounces and the gram measurements that specialty coffee ratios are actually built around.
  • Lets you compare light, medium, and strong outcomes from the same water volume without re-measuring each time.
  • Encourages weight-based measuring, which is more consistent than scooping coffee by volume.

Common Mistakes

  • Measuring coffee by scoops or cups instead of weight, which varies noticeably with grind size and bean density.
  • Confusing the water-to-coffee ratio order with the more familiar coffee-to-water phrasing used for some other brew methods.
  • Using a grind that's too fine for the roughly 4-minute steep time, which over-extracts the coffee regardless of how precisely the ratio was measured.

Edge Cases to Watch For

  • Only three preset ratios are available (1:17, 1:15, 1:12); a custom in-between ratio would need to be worked out manually using the same water-in-grams divided by ratio formula.
  • The water-to-gram conversion uses a fixed multiplier and doesn't adjust for water temperature or density variation.
  • The result is a coffee weight only; it doesn't factor in grind size or the roughly 4-minute steep time, both of which still affect how the ratio translates into cup flavor.

Common Use Cases

  • Home coffee brewers wanting a consistent starting point each time they use their French press.
  • Anyone adjusting their usual brew strength who wants to see the exact coffee weight for a lighter or stronger cup before brewing.
  • Coffee enthusiasts switching from volume-based scooping to a weight-based method for more repeatable results.
Written & fact-checked by the Calculateus TeamLast updated August 5, 2026How we verify our formulas

Frequently asked questions

Why does French press use a coarser grind than drip coffee?

A French press has no paper filter to catch fine grounds, relying instead on a metal mesh plunger that lets very fine particles through into the finished brew - a coarser grind reduces this sediment and also slows extraction to better match the longer steep time, since a fine grind steeped for 4 minutes would significantly over-extract and taste bitter.

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Conclusion

Measuring both water and coffee by weight removes a lot of the variability that comes from scooping grounds by volume, and this calculator handles the unit conversion and ratio math in one step. Pairing the resulting coffee weight with a coarse, even grind and a roughly 4-minute steep gives the ratio its best chance of translating into a balanced cup.