Coffee Ratio Calculator
Scale coffee brewing water by a selected coffee-to-water ratio.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Water mass is scaled by the selected coffee-to-water ratio. The calculator treats 1 g of water as approximately 1 ml and uses a 236.588 ml US cup. Brewed caffeine varies with the beans and extraction, so this ratio calculator does not estimate it.
Worked example
calculated with the default values below
Coffee 18 g · Strength Standard (1:16) Water 288 g · Water 288 ml · US cups 1.22 cups
General background references
Disclaimer
These calculators give general cooking guidance. Ingredient density, oven calibration, altitude and equipment all vary, and safe minimum internal temperatures always take precedence over timings. Follow the food-safety advice issued by your national authority.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
Wg = C × r; Wml ≈ Wg; cupsUS = Wml ÷ 236.588
- W
- water amount (g, equal to ml)
- C
- coffee dose in grams
- r
- brew ratio multiplier (16 = 1:16)
- cups
- cups of coffee
- caf
- approx. caffeine in mg
Water mass is treated as approximately equal to volume; US cup = 236.588 ml. Caffeine is not estimated.
Frequently asked questions
Why is caffeine not included?
Coffee-to-water ratio alone cannot reliably determine caffeine in the finished drink. Bean species and dose, grind, water, contact time and brewing method affect the amount extracted. Use a tested product or lab value if you need a caffeine amount.