Cold Brew Ratio Calculator: Coffee, Water, and Yield
Enter your target batch size, choose ready-to-drink or concentrate, pick a strength, and this calculator gives you exact coffee and water measurements in grams, tablespoons, or fluid ounces. It also accounts for absorption loss so you know the real liquid yield, and shows how many servings you get and how to dilute concentrate to a drinkable strength.
How to use this cold brew calculator
Select your unit system, choose ready-to-drink or concentrate, pick a strength preset or enter a custom ratio, and set your batch size. The calculator converts everything to grams internally and displays your coffee weight, water volume, tablespoon estimate, drinkable yield after absorption loss, and serving count. If you chose concentrate, you also get the diluted yield and serving count after a 1:1 dilution with water or milk.
Cold brew ratios explained
A cold brew ratio is written coffee:water and expresses weight, not volume. A 1:10 ratio means one gram of coffee for every ten grams of water. Ready-to-drink cold brew typically falls in the 1:8 to 1:12 range, giving a smooth, drinkable result straight from the fridge. Cold brew concentrate uses a stronger 1:4 to 1:6 ratio and is diluted with water, milk, or a milk alternative before drinking. Ratios below 1:4 can become over-extracted and bitter; ratios above 1:12 produce a light-bodied cup that may taste watery.
Why absorption matters
Coffee grounds absorb approximately 2 g of water per gram of coffee during steeping. That water stays locked in the spent grounds and is lost when you strain them out. For a 1:10 batch made with 100 g of coffee and 1,000 g of water, absorption removes about 200 g, leaving roughly 800 g of drinkable cold brew. Ignoring absorption leads to underestimating how much water you need to hit a target yield, which is why this calculator accounts for it by default. The actual absorption rate varies with grind size and steep time; coarser grinds absorb slightly less and finer grinds slightly more.
Grind size and steep time tips
Cold brew works best with a coarse or extra-coarse grind, similar to what you would use for a French press. Finer grinds extract faster but can make the brew cloudy and may over-extract if left too long. A typical steep time is 12 to 18 hours in the fridge, or 8 to 12 hours at room temperature with immediate refrigeration afterward. Longer steep times (18 to 24 hours) produce a stronger, slightly more bitter cup; shorter times leave the brew under-extracted and thin. Using filtered water noticeably improves the final flavour, as cold brew amplifies the taste of minerals and chlorine.
Cold brew ratio guide
| Style | Strength | Ratio (coffee:water) | Typical use |
|---|---|---|---|
| Ready-to-drink | Light | 1:12 | Mild, easy sipping |
| Ready-to-drink | Balanced | 1:10 | Everyday cold brew |
| Ready-to-drink | Strong | 1:8 | Bold, high caffeine |
| Concentrate | Light | 1:6 | Dilute 1:1 for a mild drink |
| Concentrate | Balanced | 1:5 | Most popular concentrate |
| Concentrate | Strong | 1:4 | Dilute 1:1.5 or more |
Standard coffee-to-water ratios by strength and style. Ratios are by weight (grams) for best precision.
Frequently asked questions
What is the best coffee-to-water ratio for cold brew?
For ready-to-drink cold brew, a 1:10 ratio (1 g coffee per 10 g water) is the most popular balanced starting point. For concentrate that you dilute before drinking, a 1:5 ratio gives a smooth result that doubles to a 1:10 cup when mixed 1:1 with water. Both are measured by weight for consistency.
How much coffee do I need for 1 litre of cold brew?
At a 1:10 ratio you add 1,000 mL of water, which requires 100 g of coffee. After accounting for absorption (roughly 200 mL), your drinkable yield is about 800 mL. To get a full litre of yield you would need to start with around 1,250 mL of water and 125 g of coffee.
Can I measure coffee by volume instead of weight?
You can use tablespoons as a rough guide, but volume measurements vary significantly with grind size and how tightly you pack the spoon. A medium-coarse grind is about 6 g per tablespoon, so the calculator shows an approximate tablespoon count. A digital scale gives far more consistent results.
How long should I steep cold brew?
In the fridge, 12 to 18 hours covers most palates. Steeping at room temperature takes less time: 8 to 12 hours is usually enough, after which you should refrigerate immediately to stop extraction and limit bacterial growth. Going beyond 24 hours in the fridge rarely improves flavour and can introduce bitter or musty notes.
How do I dilute cold brew concentrate?
The standard starting point is a 1:1 mix of concentrate and cold water or milk. If that tastes too strong, try a 1:1.5 or 1:2 ratio. If it tastes too weak, you steeped at too low a ratio and should increase the coffee amount in your next batch. The diluted-yield figures in this calculator assume a 1:1 dilution.
How long does cold brew keep in the fridge?
Undiluted cold brew concentrate keeps well for up to 2 weeks when stored in a sealed container in the fridge. Ready-to-drink cold brew is best within 1 to 2 weeks. Once diluted with milk or a plant-based alternative, treat it like any dairy product and use it within a few days.