Cold Brew Ratio Calculator
Scale a cold-brew concentrate recipe from the finished volume you want, with water absorption, brew strength, approximate grounds volume, and caffeine estimated together.
How would you like your cold brew?
Required. Enter a positive amount using a dot as the decimal separator.
Changing the unit converts the current value instead of only relabeling it.
The ratio is grams of coffee to milliliters of room-temperature water.
This is what you'll need to prepare it
Water at room temperature
1.25 US cups
Accounts for an assumed 20% liquid loss during brewing and straining.
Coffee grounds (by mass)
59.15 g
Coffee grounds (by volume)
9.86 tbsp
Caffeine content
658 mg
For 1 US cup of strong concentrate, start with 1.25 US cups of water and about 59.15 g of coffee.
Enter a complete valid volume to rebuild the recipe. Download Excel will become available again automatically.
Recipe detail
| Item | Amount | Role in the recipe |
|---|---|---|
| Finished concentrate | 1 US cup | Target strained yield |
| Room-temperature water | 1.25 US cups | Starting liquid before absorption loss |
| Coffee grounds | 59.15 g | Strong 1:5 coffee-to-water ratio |
| Estimated caffeine | 658 mg | Approximation based on coffee dose |
Ground-coffee volume is an approximation because grind size, roast, and how tightly the spoon is filled change bulk density. For repeatable brewing, use the mass result with a kitchen scale.
How to use the cold brew ratio calculator
What this calculator does
This calculator estimates the starting water and coffee grounds needed to produce a chosen amount of strained cold-brew concentrate. It follows a simple immersion-brew model: the finished concentrate is assumed to be about 80% of the starting water volume, while the selected Strength sets the coffee-to-water ratio. It also reports an approximate Caffeine content. The caffeine figure is a planning estimate, not a laboratory measurement, because bean species, roast, grind, extraction time, and dilution can all change the actual amount.
When to use it
Use it when you want to scale a batch to a pitcher or bottle, compare light versus strong concentrate without doing ratio arithmetic, convert a recipe between US cups, fluid ounces, milliliters, and liters, or estimate how much coffee to grind before a 12 – 24 hour steep. Research on cold brewing shows that grind size and contact time affect extraction and sensory results, so treat ratio as one controllable part of the process rather than the only quality variable; see this peer-reviewed cold-brew extraction study in PubMed Central.
How to calculate
- The calculator opens with a ready-to-use demonstration: 1 US cup of strong concentrate. The example is already calculated and its Excel workbook is immediately available.
- Replace Volume of coffee concentrate with the strained amount you want. Positive decimals are accepted; use a period for decimals. Then choose the matching Volume unit. If you change units after entering a value, the calculator converts the value so the physical volume stays the same.
- Choose Strength: Light uses 1:5.6, Regular uses 1:5.3, and Strong uses 1:5. The second number is milliliters of water per gram of coffee.
- Read Water at room temperature, Coffee grounds (by mass), Coffee grounds (by volume), and Caffeine content. The recipe table repeats the same canonical values in a compact preparation plan.
- Select Download Excel to export the current validated recipe as a real XLSX workbook. Reset clears the demonstration and calculated data; Excel export then stays disabled until a complete valid volume is entered again.
Input guide
Volume of coffee concentrate is required and must be a positive finite number. For example, enter 1.5 for one and a half selected units. A larger finished volume scales water, grounds, and estimated caffeine proportionally. Do not paste scientific notation or decimal-comma forms such as 1,5; they are rejected to prevent ambiguous interpretation. Volume unit is required and may be US cups, US fl oz, mL, or L. The conversion is physical, so changing from 1 US cup to mL produces about 236.59 mL rather than leaving the numeric value unchanged. Strength is required. Light uses less coffee for the same water, Regular sits between the presets, and Strong uses the 1:5 ratio. Strength does not change the target finished volume; it changes the grounds dose and caffeine estimate.
Output guide
Water at room temperature is the starting liquid quantity. It is 25% higher than the target concentrate because the model divides desired yield by 0.8. Coffee grounds (by mass) is the preferred preparation quantity because mass is much more repeatable than scoops. Coffee grounds (by volume) is an approximate tablespoon conversion using 6 g per US tablespoon, near the commonly cited rough range of 5 – 7 g per tablespoon for ground coffee; use it only when a scale is unavailable. Caffeine content estimates total caffeine in the undiluted concentrate from the calculated coffee dose. A larger batch or stronger ratio increases it. The live Brew ratio, Yield assumption, Steep target, and Estimated caffeine pills summarize the active recipe and assumptions.
Worked example
The startup example asks for 1 US cup of Strong – 1:5 concentrate. One US cup is about 236.59 mL. With an 80% retained-liquid assumption, starting water is 236.59 ÷ 0.8 = 295.74 mL, which is 1.25 US cups. At 5 mL of water per gram of coffee, the grounds dose is 295.74 ÷ 5 = 59.15 g. At the calculator's dose-based caffeine factor, that batch is approximately 658 mg of caffeine before dilution. Because caffeine varies substantially among coffees and brewing conditions, compare this estimate with package or roaster information when available. The U.S. FDA notes that individual caffeine sensitivity varies and discusses daily intake in its consumer guidance on caffeine.
How the cold-brew ratio model works
The calculator uses two linked relationships. First, it estimates the water required to achieve the requested strained yield. If 80% of starting water remains as concentrate, the starting-water formula is:
starting water = desired concentrate ÷ 0.80
Second, coffee mass is calculated from the selected water-to-coffee ratio. A strong 1:5 recipe means one gram of coffee for each five milliliters of water, while 1:5.6 uses fewer grounds for the same liquid. This keeps the model dimensionally consistent: water is converted internally to milliliters, divided by mL/g, and returned as grams.
The 80% yield assumption is a practical simplification. Actual retained liquid changes with grind, filter material, draining or squeezing, coffee dose, and equipment geometry. Treat the result as a reproducible starting recipe and adjust future batches from measured yield. The same is true of sensory character: peer-reviewed work has found that cold and hot brew pH can overlap even while titratable acidity differs. For context, review the Scientific Reports study on cold-brew acidity and antioxidant activity.
Practical brewing notes and common mistakes
- Weigh the coffee when possible. Spoon volume changes with grind size and packing, so mass is the better control variable for repeatable batches.
- Do not confuse the ratio direction. Here 1:5 means 1 gram of coffee for 5 mL of water, not five grams of coffee per milliliter.
- Remember that this is concentrate. Many people dilute cold-brew concentrate with water, milk, or ice before drinking. Any dilution reduces caffeine per serving even though the batch total stays the same.
- Use time and grind as separate levers. Changing the ratio affects dose, while grind and contact time affect extraction. Coarser grounds are commonly used for long immersion to simplify filtration.
- Measure your own yield after straining. If your brewer consistently retains more or less liquid than the 20% assumed loss, use the calculator as a baseline and note your actual correction for the next batch.
Caffeine values can vary widely even at the same recipe ratio. This tool is for recipe planning and unit conversion, not for determining a medically safe dose.