Food & Cooking

Coffee Ratio Calculator

What this does

Find the coffee dose for any amount of water at classic brew ratios, with a strength guide and cup conversions.

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Calculator inputs

Using the coffee ratio calculator

  1. 01

    Weigh your water

    Enter the water you will pour in grams or milliliters; a kettle scale makes this trivial.

  2. 02

    Pick a ratio

    Start at 1:16. Drop toward 1:15 for immersion brewers or dark roasts; stretch to 1:18 for bright pour-overs.

  3. 03

    Grind to the number

    Grind exactly the displayed grams. If the cup tastes thin, grind finer; bitter and harsh means grind coarser.

Why grams beat scoops

A “tablespoon of coffee” can vary 30% bean to bean depending on roast level and grind size, while a gram is a gram. Once you switch to weighing both dose and water, reproducibility problems mostly vanish; this calculator supplies the arithmetic.

Ratio is a strength dial, not a flavor dial

Changing the ratio changes extraction yield and concentration together. Too weak? Before blaming beans, check whether your grind, time or temperature is off; ratio fixes concentration, technique fixes character.

Absorbed water and bypass

Grounds hold nearly their own weight in water after brewing. That is why ratios quote total pour water; if you brew in a French press, the drinkable yield is smaller than what you poured; plan accordingly for guests.

The math behind this calculator

Coffee(g) = Water(g) ÷ Ratio Cups ≈ Water(ml) ÷ 250

Brew ratios compare coffee mass to water mass: 1:16 means one gram of grounds per sixteen grams of water. Because a milliliter of hot water weighs almost exactly one gram, any ml volume doubles as its gram weight. The dose divides water weight by the chosen ratio.

Assumptions & limitations

  • Water weight equals water volume (1 g ≈ 1 ml).
  • Ratios refer to total brew water, including what grounds absorb (~2 g per g of coffee).
  • A “cup” is taken as a generous 250 ml mug, not the 150 ml coffee-industry cup.

Worked example

Brewing 500 g of water at the balanced 1:16 ratio calls for 31.25 grams of ground coffee; roughly two 250 ml mugs’ worth.

Frequently asked questions

Is 1:16 good for every method?
It is a solid default for drip and pour-over. Immersion methods often taste better slightly stronger (1:15), espresso uses radically different ratios near 1:2.
Does 500 ml of water really weigh 500 g?
Essentially yes within typical brewing temperatures; the 1:1 assumption introduces less error than most kitchen scales.
How much coffee for a full 12-cup machine?
The carafe “cups” are ~150 ml each, so 12 cups ≈ 1800 ml ÷ 16 = about 112 grams. Enter 1800 above to confirm.
Should I adjust for light roasts?
Light roasts extract slower; many brewers tighten the grind or extend contact time before touching the ratio.

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