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Choose the volume you know before entering the two ratio denominators.
Changing the unit converts the displayed value without changing the physical quantity.
The calculator solves backward for concentrate and added liquid.
This is a recipe-planning ratio, not a measured TDS value.
1 :
Tune the ready-drink target from 1:1 to 1:40.
1 : {{ formatNumber(target_ratio, 1) }}
Serving count uses pourable yield after any service-loss allowance.
Ice melt is handled separately in Advanced.
The remaining measured dilution is water.
{{ formatNumber(milk_percent, 0) }}%
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Zero uses all entered concentrate.
{{ formatNumber(reserve_percent, 0) }}%
Zero is appropriate for bottled or no-ice service.
{{ formatNumber(ice_melt_percent, 0) }}%
Zero treats the full finished batch as pourable.
{{ formatNumber(service_loss_percent, 0) }}%
Exact is the neutral default.
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Service scaleFinishedConcentrateWaterMilkIceServingsCopy
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Adjustment brief

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Coffee to Water Ratio Calculator Plan a repeatable coffee-to-water ratio from a weighed dose or target cup yield, including retained water and method-specific starting ranges.
Iced Coffee Flash Brew Calculator Plan flash-brew iced coffee with a balanced coffee dose and hot-water-to-ice split plus pour timing and an idealized chill estimate.
Grind Size Chooser Choose a coffee grind size from brew method and measured time with taste feedback, calibrated grinder mapping, and clear dial-in warnings.
Coffee Drink Calorie Calculator Estimate coffee drink calories from a measured recipe and see which ingredients drive the total before comparing milk, syrup, or cream swaps.

Cold brew concentrate separates brewing from service. A strong filtered base can be prepared once, then diluted for a black drink, a milk-forward pour, an iced serving, bottles, or a larger batch. Consistency depends on measuring the concentrate that actually passed through the filter, not the water originally poured over the grounds.

Ratio notation can be counterintuitive. If concentrate is described as 1:5 and the ready drink as 1:10, the larger second number represents a weaker drink because the same coffee reference is spread through more liquid. Moving from 1:5 to 1:10 doubles the final volume when all available concentrate is used.

Concentrate ratio
The water side of the recipe used to brew the filtered base.
Target ratio
The planned strength after dilution liquid and expected ice melt are counted.
Pourable yield
Finished volume after the service-loss allowance, used to estimate servings.

Water, milk, and ice all contribute to final volume, but they are prepared differently. Expected ice melt reduces the measured liquid added before service. A water-and-milk split divides only the remaining measured dilution. Service loss is different again: it reduces usable servings without changing the recipe amounts.

  • A reserve holds back part of available concentrate before the batch is scaled.
  • Ice allowance belongs inside total dilution, not on top of the target batch volume.
  • Milk share applies only when a water-and-milk split is selected.
  • Pour rounding changes displayed prep amounts, not the underlying ratio calculation.

Cold-brew ratio is a planning convention, not a laboratory strength reading. It does not reveal total dissolved solids, extraction yield, caffeine, sweetness, shelf life, or food-safety status. Grind, steep time, roast, water, filtration, storage, and serving temperature still need to be controlled and the mixed drink still needs to be tasted.

A target ratio at or below the concentrate ratio does not create a dilution recipe. In that case, no water, milk, or ice is added and the available concentrate remains the finished batch. This is useful as a warning that the ratio direction may have been reversed.

How to Use This Tool:

Begin with the volume that is fixed: filtered concentrate on hand or a finished batch that must be produced.

  1. Choose the known volume. Under Solve from, use Concentrate available to find total yield, or Finished batch target to work backward to the concentrate required.
  2. Enter both ratio denominators. The target denominator normally needs to be larger than the concentrate denominator for dilution to occur.
  3. Set serving and liquid assumptions. Choose water, milk, or a split; then add reserve, ice-melt, and service-loss percentages only when the service plan needs them.
  4. Review the recipe warning and pourable servings. If the ice allowance consumes all available dilution or the target is not weaker than the concentrate, correct the ratios or service assumptions before batching.

Interpreting Results:

Finished batch is the planned volume after concentrate, measured dilution, and ice allowance are combined. Pourable volume is smaller when service loss is entered, and serving count is based on that pourable amount rather than the mixed recipe.

  • A target from 1:8 through 1:12 receives the ready-range label; below 1:8 is labeled bold and above 1:12 is labeled light.
  • A target denominator less than or equal to the concentrate denominator is marked for review because no dilution is added.
  • Use the package ladder for scaling, but taste a small sample before committing a full pitcher, bottle run, or keg.

Technical Details:

The model treats the two ratio denominators as proportional volume references. Volumes are normalized to milliliters before dilution, loss, and serving calculations, then converted back to the selected display units.

Formula Core

When the target drink is weaker than the concentrate, final volume scales by the ratio of the two denominators.

Vf=VcRtRc

For a fixed finished batch, the equation is rearranged to find required concentrate.

Vc=VfRcRt
TermCalculationMeaning
Usable concentrateEntered concentrate × (1 − reserve %)Concentrate available to mix
Total dilutionFinished volume − concentrateAll water, milk, and expected ice melt
IceSmaller of total dilution or finished volume × ice %Expected melt counted inside the batch
Measured dilutionTotal dilution − iceWater and milk physically measured
Pourable volumeFinished volume × (1 − service loss %)Usable serving yield
ServingsPourable volume ÷ serving sizeFractional servings are retained

For a split dilution, milk equals measured dilution multiplied by milk share and water is the remainder. A milk-only plan assigns all measured dilution to milk; a water-only plan assigns it all to water. Requested ice is capped at total dilution so measured water and milk never become negative.

Boundaries and precision

  • Concentrate ratio accepts 1:1 through 1:30; target ratio accepts 1:1 through 1:40.
  • Reserve is limited to 0% through 50%, ice allowance to 0% through 25%, and service loss to 0% through 20%.
  • US fluid ounce, cup, quart, and gallon conversions use 29.5735295625, 236.5882365, 946.352946, and 3785.411784 mL respectively.
  • Pour-rounding choices are exact, 1, 5, 10, or 25 mL. Full-precision values remain the basis for scaling and serving count.

Worked Examples:

Five-liter split batch

A 5 L target made from 1:5 concentrate at a 1:11 drink ratio needs about 2272.73 mL concentrate. With 5% ice allowance, 250 mL of the batch is assigned to melt. Splitting the remaining dilution at 35% milk gives about 867.05 mL milk and 1610.23 mL water. A 4% service loss leaves 4800 mL, exactly 20 servings of 240 mL.

References: