What Is the Cold Brew Ratio Calculator?
Cold brew coffee is made by steeping ground coffee in cool or room-temperature water for 12–24 hours. Unlike hot brewing, there's no precise temperature to manage — the single most important variable is the coffee-to-water ratio. This calculator tells you exactly how many grams of ground coffee to use for any amount of water, so you can scale a small jar or a large batch with confidence.
How to Use It
Enter the volume of water you plan to use in millilitres, then choose your ratio. A ratio of 1:8 means 1 gram of coffee for every 8 millilitres (or grams) of water — a strong concentrate you dilute before drinking. For a ready-to-drink brew, use 1:15 to 1:17. The calculator divides the water by the ratio to give the coffee mass and estimates the total concentrate yield.
The Formula Explained
The math is simple: $$\text{Coffee (g)} = \frac{\text{Water (mL)}}{\text{Ratio}}$$. Because 1 mL of water weighs about 1 gram, the ratio works the same whether you measure by weight or volume. A higher ratio number (e.g. 1:16) uses less coffee and yields a lighter brew; a lower number (e.g. 1:5) gives an intense concentrate.
Worked Example
You want to brew with 1,000 mL of water at a classic concentrate ratio of 1:8. $$\text{Coffee} = \frac{1000}{8} = 125 \text{ grams}$$ of ground coffee. The approximate concentrate yield is the water plus the absorbed grounds, about 1,125 mL before straining (grounds retain some liquid in practice).
FAQ
What ratio should beginners use? Start with 1:8 for a concentrate you dilute 1:1 with water or milk, or 1:15 for a brew you drink straight.
Coarse or fine grind? Use a coarse grind for cold brew to avoid over-extraction and a muddy cup.
How long should I steep? 12–18 hours at room temperature, or up to 24 hours in the fridge for a smoother result.
