Use the Coffee Ratio Calculator
Use this calculator to solve for Water amount, Coffee amount, or Brew ratio from the other two values. Coffee and water use grams or ounces; the ratio is the unitless N in 1:N.
Coffee-to-Water Ratio Formula
A ratio of 1:N means 1 part coffee to N parts water by weight. The calculator uses these equations:
Water = Coffee x NCoffee = Water / NN = Water / Coffee
It assumes 1 gram water = 1 milliliter water. Coffee and water amounts use the selected weight unit, while N has no unit.
How to Use the Calculator
- Choose an option from Solve for: Water amount, Coffee amount, or Brew ratio.
- Choose grams (g) or ounces (oz) from Weight unit. This applies to coffee and water amounts.
- Enter the two non-solved values. For Ratio (1 : N), enter only N, such as
16. - Changing Solve for hides the field being calculated.
- Click Calculate.
Read, Copy, or Download the Result
After you click Calculate, the result section shows four summary statistics. The Formula used block lists the formulas and the water-equivalence assumption. The result table shows entered values, calculation rows, and final values. Summary values use two decimal places; intermediate values use three.
Use Copy result to copy the plain-text summary through the browser clipboard. Copying can fail and show Could not copy - select and copy manually. The result textarea is hidden, so this fallback is not an always-available manual-selection workflow. Use Download result (.txt) to save coffee-ratio-calculator-result.txt.
Reset, Validation, and Limitations
Click Reset to restore Solve for to Water amount, Weight unit to grams (g), coffee to 20, water to 320, and ratio to 16. It also clears errors and hides the result.
The two non-solved fields must contain finite numbers greater than zero. Missing, invalid, or zero values produce an error instead of a result.
- The calculation uses the values you enter and does not recommend a ratio.
- It does not account for water absorbed by coffee grounds or estimate final brewed liquid yield.
- It does not fetch brew guides or apply a coffee association's or roaster's ratio convention.
- It is a mathematical calculation, not professional brewing advice.
Calculator Input Handling
The calculator script performs the calculation locally in your browser and does not submit calculator values. This describes the calculator inputs only; other page features may use their own forms.
Frequently Asked Questions
What is the coffee-to-water ratio formula?
Ratio is expressed as 1 part coffee to N parts water by weight. Water = Coffee x N. Coffee = Water / N. N = Water / Coffee. All three values are related by this single equation; enter any two and the calculator solves for the third.
Is coffee ratio measured by weight or volume?
This calculator measures coffee and water by weight in grams or ounces. The ratio is unitless. It assumes 1 gram of water equals 1 milliliter of water and does not convert scoops, tablespoons, or cups.
What ratio should I use for coffee?
This tool does not recommend a ratio. It computes the missing value from the coffee amount, water amount, or ratio you enter, without applying a preferred ratio automatically.
Does this include water absorbed by the coffee grounds?
No. This tool calculates the input coffee-to-water ratio only. It does not account for water absorbed by coffee grounds or estimate final brewed liquid yield.
Does this tool use a standardized brewing database or official rules?
No. It performs a single, transparent calculation using only the values you type in. It does not fetch brew guides or apply any coffee association's or roaster's specific ratio convention, and it is not professional brewing advice.