Cold Brew Calculator
Turn any coffee-to-water ratio into exact cold brew amounts, steep time, yield and dilution.
Enter an amount — the recipe updates as you type.
- Ground coffee
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- Brew water
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- Brew ratio
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- Concentrate yield
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- Dilution (concentrate : water)
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- Water to add
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- Drinkable total
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- Servings
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- Steep time
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- Grind
- Coarse
How it works
Cold brew is measured as a brew ratio by weight: 1 part ground coffee to N
parts water, with water counted at 1 g = 1 ml. From whichever number you know, the calculator
solves the other two: water = ratio × coffee, coffee = water ÷ ratio.
Concentrates usually sit between 1:4 and 1:8; a batch you drink straight from the fridge is
nearer 1:12 to 1:15.
The liquid you actually pour off is smaller than the water you added, because the grounds soak
some up. This tool uses the standard immersion figure of 2 ml retained per gram of coffee, so
yield = water − 2 × coffee. That also makes the dilution honest: the concentrate
you are holding is 1 part coffee to (N − 2) parts liquid, so to reach a drinking strength of
1:T you add (T − (N − 2)) ÷ (N − 2) parts water. A 1:5 batch from 1000 ml of water
gives 200 g of coffee and 600 ml of concentrate; diluted 1 : 3 that is 2400 ml at 1:12 —
ten 240 ml servings. Real-world retention varies with grind and how hard you press the
filter, so treat the yield as a very good starting point rather than a law.
Steep times follow the common guidance: roughly 12–16 hours at room temperature or 18–24 hours in the fridge, always with a coarse, sea-salt-sized grind so the brew stays clean and easy to filter. Everything is arithmetic done in your browser — nothing is uploaded, no sign-up, no ads.
Frequently asked questions
What is the best coffee-to-water ratio for cold brew?
For a concentrate you dilute before drinking, 1 part coffee to 4-8 parts water by weight is the usual range, with 1:5 the most common starting point. If you want to pour the batch straight over ice, brew weaker at about 1:12 to 1:15. Water is counted at 1 g = 1 ml, so 200 g of coffee to 1000 ml of water is a 1:5 brew.
How long should cold brew steep?
Roughly 12-16 hours at room temperature or 18-24 hours in the fridge, using a coarse, sea-salt-sized grind. Colder water extracts more slowly, which is why the fridge needs the longer window. Past about 24 hours the gains are small and the brew starts to taste woody, so filter it out and refrigerate the finished coffee.
How much water should I add to cold brew concentrate?
It depends on how strong you brewed. The grounds keep about 2 ml of water per gram, so a 1:5 batch leaves concentrate that is really 1 part coffee to 3 parts liquid; adding 3 parts water brings it to a 1:12 drinking strength. The calculator does this for you and shows the exact volume of water to add and how many servings you end up with.