Coffee Ratio Calculator

Created by Łucja Zaborowska, MD, PhD candidate
Reviewed by Anna Szczepanek, PhD and Jack Bowater
Last updated: Jan 18, 2024

Welcome to the coffee ratio calculator! We'll take you on an exciting journey to the world of coffee measurements and unique methods of coffee preparation. ☕

We'll teach you how to calculate coffee-to-water ratios and show you how much coffee per cup you really need, depending on the given method.

Read on to discover how to use this tool, and visit our other coffee-related tools, such as cold brew ratio calculator and coffee kick calculator, to learn how to prepare your cold brew coffee concentrate, and find out the level of alertness depending on the time you've slept and the dose of caffeine you've ingested.

How to calculate coffee ratios?

It's already easy, but we're gonna make it even easier:

  1. Choose your desired coffee ratio.

    We decided on 9:40, because it seems trickier than the others. 🙃

  2. Decide on the final volume of coffee you'd like to make.

    We chose 250mL (8.5 US fl oz).

  3. Let's calculate!

  • Altogether, we need 49 parts of the drink (9:40, 9+40)
  • We'll use two equations:

Coffee volume = (Total volume/Total parts) × Coffee parts

Water volume = (Total volume/Total parts) × Water parts

💡 We need to assume that 1 mL = 1 g.

The coffee-to-water ratio is 9:40, so we'll need 9 parts coffee and 40 parts water.

Coffee volume = (250 mL/49) × 9

Coffee volume = 45.9 mL = 45.9 g

Water volume = (250 mL/49) × 40

Water volume = 204.1 mL

There you go! We need 45.9 g of coffee and 204.1 mL of water.

💡 This calculation doesn't take into account the loss of water during the process. However, our coffee water calculator does take this into consideration.

While you're here, you might like to take some time to look at our other caffeine-filled tools. Assess the amount of coffee you need and find out what a lethal dose of caffeine is by using Omni coffee calculator and caffeine calculator, respectively.

How to calculate French press ratio?

The typical French press coffee to water ratio is 1:12. It means that for every 1 g of coffee, we'll need 12 mL of water.

You can simply calculate how much water you'll need for a given amount of coffee using the equation below:

Amount of water you need(mL) = Amount of coffee you have(g) × 12

How to calculate coffee ratio for espresso?

The coffee ratio for espresso is unique - due to the small amount of water we use, we need to take care of every single drop. 💧

That's why, to achieve a perfect 1:2 coffee grounds to water ratio, we need to use the 1:3.6 ratio instead. (We need to make up for water losses in the coffee machine - the so-called coffee cake absorbs about 80% of it!)

Amount of water you need(mL) = Amount of coffee you have(g) × 3.6

Alternative coffee chart

Does anybody needs a V60 calculator? 🍵 Let's break down all the ratios one by one!






The smallest coffee, also called caffè corto.



Watch out for water loss! To achieve a 1:2 ratio, use 1:3.6 instead.



25 s, 88-92°C, results in 25 mL of coffee.

Cold Brew


Takes 12-24 h to make!

Moka Pot


Coffee from the stovetop.



Making one cup at a time.

French Press


The easiest to use.



So-called drip coffee.



Have you ever dreamt of becoming an alchemist?



Blooming coffee in an hourglass.


How to calculate coffee beans to water ratio?

Our coffee measurements need a few assumptions:

  • 1 g = 1 mL
  • 1 coffee bean weights 0.13g (0.0046oz)

If your desired ratio is, e.g., 1:6, you'll need 1 portion of coffee and 6 portions of water.

  1. For every 1 g of coffee, you'll need 6 mL of water.
  2. For every 1 g of coffee, you'll need ~8 coffee beans.
  3. All together, you'll need around 8 coffee beans for every 6 mL of water you want to use.
Łucja Zaborowska, MD, PhD candidate
How many cups of coffee?
Coffee : water ratio
1:11 (Aeropress)
Ground coffee
US fl oz
Final coffee volume
US fl oz
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