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AI Calculator

Generated on demand with DeepSeek AI

Food & Cooking

Coffee Water Ratio Calculator.

Calculates the exact amount of water needed for a given dose of coffee grounds at any brew ratio, plus the resulting beverage yield.

Results update live as you type.
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Your inputs

How it works

  1. 1

    Weigh your dry coffee dose in grams.

  2. 2

    Choose a brew ratio (e.g., 1:16 for pour-over).

  3. 3

    Multiply the dose by the ratio to get total water in grams.

  4. 4

    Subtract the water retained by the grounds to estimate the brewed yield.

coffee_grams * ratio

Frequently asked questions

What does a 1:16 ratio mean?

It means 1 gram of coffee for every 16 grams of water. So 18 g of coffee needs 288 g of water.

Why subtract retained water?

Coffee grounds absorb roughly 2 grams of water per gram of coffee. That water stays in the grounds and does not end up in your cup.

Can I use this for espresso?

Yes, but espresso ratios are much tighter (1:2 to 1:3). Set the ratio field to 2 or 3 for espresso-style brewing.

Results

Formula checked

Water needed

288g

Brewed coffee yield252.0g
Water per cup (approx. 150 ml)144.0g
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AI-generated estimate for general guidance only — not professional advice.

How it works

Calculates the exact amount of water needed for a given dose of coffee grounds at any brew ratio, plus the resulting beverage yield.

  1. Weigh your dry coffee dose in grams.
  2. Choose a brew ratio (e.g., 1:16 for pour-over).
  3. Multiply the dose by the ratio to get total water in grams.
  4. Subtract the water retained by the grounds to estimate the brewed yield.

Formulas

The math behind this calculator, written out so you can verify the result.

Water needed

Water (g) = Coffee dose (g) × Brew ratio

The brew ratio tells you how many grams of water to use for each gram of coffee.

Example:

Input: Coffee = 18 g, ratio = 16

Calculation: 18 × 16

Result: 288 g water

Brewed yield

Yield (g) = Water (g) − (Coffee dose × Retention)

Grounds soak up about 2 g of water per gram of coffee, so the liquid in your cup is less than the water you poured.

Example:

Input: Water = 288 g, coffee = 18 g, retention = 2

Calculation: 288 − (18 × 2)

Result: 252 g brewed coffee

Real-world use cases

Where this calculation shows up in everyday life.

Pour-over brewing

Dial in a precise water amount for V60, Chemex, or Kalita brewers.

Example: 18 g coffee at 1:16 needs 288 g water.

Batch brewing

Scale up for a full carafe while keeping the same ratio.

Example: 60 g coffee at 1:15 needs 900 g water.

Espresso and strong brews

Use low ratios (1:2 to 1:3) to calculate espresso-style doses.

Example: 18 g coffee at 1:2 needs 36 g water.

Tips and common mistakes

Tips

  • Weigh water in grams on a scale; 1 g of water is about 1 ml.
  • Start with 1:16 for pour-over and 1:15 for drip, then adjust to taste.
  • Use the brewed yield to plan cup size, not the total water poured.
  • Keep notes on ratio and grind size to repeat good brews.

Common Mistakes to Avoid

  • Confusing coffee-to-water ratio with water-to-coffee ratio (1:16 is not 16:1).
  • Forgetting that grounds retain water, so the cup holds less than you poured.
  • Measuring coffee by volume (scoops) instead of weight, which varies widely.