Coffee to Water Ratio Calculator
Find the perfect coffee-to-water ratio for your preferred brewing method. Our calculator supports general formula, French press, pour over, drip coffee, and cold brew methods. Calculate instant conversions between coffee and water amounts to achieve your ideal coffee strength.
Last updated: January 26, 2026
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The ratio is automatically set based on brew type and strength. You can also enter a custom ratio.
Coffee to Water Ratio Explained
The coffee to water ratio is the foundation of great coffee brewing. It determines how strong or weak your coffee will taste. The ratio is expressed in weight units for precision, as coffee density can vary significantly based on grind size and bean type.
Understanding the Ratio
A 1:18 ratio means:
- 1 gram of coffee for every 18 grams (or milliliters) of water
- For 500ml of water, you need approximately 28 grams of coffee
- This produces a balanced, regular-strength cup of coffee
Why use weight instead of volume? Coffee grounds can vary in density based on how they're ground and packed. A tablespoon of finely ground coffee weighs more than a tablespoon of coarsely ground coffee. Using weight (grams) ensures consistent results regardless of grind size.
Water, on the other hand, has a consistent density of approximately 1 gram per milliliter at room temperature, so volume measurements work well for water. This is why our calculator allows you to measure coffee by weight and water by volume.
Coffee Ratios by Brewing Method
Regular strength
1:18 ratio
1 gram coffee per 18ml water
Strong coffee
1:15 ratio
1 gram coffee per 15ml water
Recommended by the Specialty Coffee Association (SCA) for balanced extraction
Regular strength
1:17 ratio
1 gram coffee per 17ml water
Strong coffee
1:11 ratio
1 gram coffee per 11ml water
French press typically needs more coffee due to longer extraction time
Regular strength
1:17 ratio
1 gram coffee per 17ml water
Strong coffee
1:15 ratio
1 gram coffee per 15ml water
Similar to general formula, optimized for filter brewing methods
Regular strength
1:8 ratio
1 gram coffee per 8ml water
Strong coffee
1:5 ratio
1 gram coffee per 5ml water
Cold extraction is less efficient, requiring more coffee for proper strength
How to Use the Coffee to Water Ratio Calculator
Step-by-Step Instructions
- Choose your brewing method - Select from general formula, French press, drip/pour over, or cold brew
- Select coffee strength - Choose regular or strong based on your preference
- Enter water or coffee amount - Input either the amount of water you have or the amount of coffee you want to use
- Select units - Choose your preferred units (ml, cups, oz for water; g, oz, lb for coffee)
- Get instant results - The calculator automatically shows the corresponding amount of the other ingredient
Example Calculation
Scenario: You want to make 500ml of regular-strength French press coffee
- Brew type: French press
- Strength: Regular (1:17 ratio)
- Water: 500ml
- Result: You need approximately 29.4 grams of coffee
The calculator works bidirectionally - enter water amount to get coffee amount, or enter coffee amount to get water amount. The ratio is automatically set based on your brewing method and strength preference, but you can also enter a custom ratio if you want to experiment.
Tips for Perfect Coffee
While the coffee-to-water ratio is crucial, several other factors contribute to brewing the perfect cup:
Use filtered or spring water. Hard water can make coffee taste bitter, while distilled water lacks minerals that enhance flavor. The Specialty Coffee Association recommends water with balanced mineral content.
Always grind coffee beans fresh just before brewing. Pre-ground coffee loses flavor quickly. Match grind size to your brewing method: coarse for French press, medium for pour over, fine for espresso.
Water temperature should be between 195-205°F (91-96°C) for hot brewing methods. Too hot extracts bitter compounds; too cold results in weak, under-extracted coffee.
Extraction time varies by method: 4-5 minutes for French press, 3-4 minutes for pour over, 12-48 hours for cold brew. Follow recommended times for your chosen method to avoid over or under-extraction.
Frequently Asked Questions
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