600
ml
400
ml
800
ml
3.3
servings
167
g/L
16
hr
600
ml
400
ml
800
ml
3.3
servings
167
g/L
16
hr
Cold brew coffee has surged in popularity because of its naturally sweet, smooth, low-acidity taste profile. Unlike hot brewing methods that extract flavors in minutes with near-boiling water, cold brew relies on time — anywhere from 8 to 24 hours — and cold or room-temperature water to gently extract compounds from coarsely ground coffee. The result is a concentrated or ready-to-drink beverage that many coffee enthusiasts consider superior to iced coffee, which is simply hot-brewed coffee poured over ice.
The Cold Brew Ratio Calculator takes the guesswork out of measuring by helping you determine exactly how much water to use for a given amount of ground coffee. The core variable is the water-to-coffee ratio, which directly controls the strength of your final brew. A lower ratio (like 1:5) produces a thick, syrupy concentrate meant to be diluted before drinking, while a higher ratio (like 1:15) gives you a ready-to-drink brew at full strength.
For cold brew concentrate, ratios typically range from 1:5 to 1:8. This means for every gram of coffee, you use 5 to 8 milliliters of water. Concentrate is ideal for making large batches efficiently — you dilute it with water, milk, or a milk alternative when serving. A ratio of 1:6 is a widely loved starting point for concentrate.
For ready-to-drink cold brew, ratios generally fall between 1:12 and 1:17. These batches can be poured straight from the fridge into a glass of ice without dilution. Specialty coffee shops often target 1:14 to 1:15 for a balanced cold brew that highlights the natural sweetness of the beans without being too weak or too overpowering.
Steep time also plays a major role. Most cold brews are steeped between 12 and 24 hours, typically in the refrigerator. Steeping at room temperature is faster (12 to 15 hours) but carries a slightly higher risk of over-extraction. Refrigerator steeping is more forgiving and produces a cleaner, crisper cup. The calculator lets you choose your steep time so you can plan when to start your batch.
Grind size matters greatly in cold brew. A coarse grind — similar to rough sea salt — is essential. Too fine a grind leads to over-extraction and an astringent, bitter brew. Too coarse and the flavors remain underdeveloped. Once steeped, filter the grounds through a fine mesh strainer, cheesecloth, or a dedicated cold brew filter bag.
With this calculator, you can confidently scale your recipe whether you're making a single serving or a large-batch brew for the whole week.
The calculation is straightforward. Given your chosen coffee weight in grams and the water-to-coffee ratio, the water volume is calculated as:
Water (ml) = Coffee (g) × Ratio
For example, 100 g of coffee at a 1:6 ratio requires 600 ml of water. The total estimated yield approximates the final brew volume after accounting for the coffee grounds absorbing some water (roughly 1–2 ml per gram of coffee). Servings are calculated by dividing the total brew by a standard serving size of 240 ml (8 oz). The steep time entered is reflected directly in the output to help you plan your schedule.
If your output shows fewer than 2 servings, consider scaling up your coffee and water proportionally. If using a concentrate ratio (1:5–1:8), remember to dilute 1:1 with water or milk when serving — so your effective serving count doubles. A ratio below 1:5 risks under-extraction; above 1:17 may produce a thin, watery result. Sweet spot for concentrate: 1:6. Sweet spot for ready-to-drink: 1:14 to 1:15.
Inputs
Results
200g coffee × 6 = 1200ml water. After 20 hours of steeping, you get ~5 servings of concentrate (each diluted 1:1 gives 10 drinking portions of ~240ml).
Inputs
Results
30g coffee × 14 = 420ml water. Steep 18 hours for approximately 1.75 servings of ready-to-drink cold brew.
A ratio of 1:6 (coffee to water) is an excellent starting point for concentrate, and 1:14 for ready-to-drink. These ratios produce a well-balanced flavor that you can adjust based on taste preferences after your first batch.
Yes. Room-temperature steeping is faster, typically 10–15 hours, and can produce a slightly different flavor profile. However, refrigerator steeping (18–24 hours) is safer from a food-safety perspective and produces a cleaner, crisper cup.
Always use a coarse grind, similar to rough sea salt. A finer grind leads to over-extraction, producing an astringent, bitter result that is difficult to correct.
Cold brew concentrate keeps well for up to 2 weeks when stored in an airtight container in the refrigerator. Ready-to-drink cold brew is best consumed within 1 week for optimal freshness.
Concentrate (ratios 1:5 to 1:8) must be diluted before serving, usually 1:1 with water or milk. Ready-to-drink (ratios 1:12 to 1:17) can be poured straight over ice without further dilution.
Yes. Filtered or spring water significantly improves the taste of cold brew. Hard tap water with high mineral content can dull the flavors. Ideally, use water with a TDS (total dissolved solids) of 50–150 ppm.
Yes, but medium to dark roast coffees tend to shine in cold brew, offering chocolatey, caramel, and nutty notes. Light roasts can work but may taste fruity or acidic in the final cup.
Bitterness is usually caused by too fine a grind, too high a ratio, or over-steeping beyond 24 hours. Try a coarser grind, reduce your steeping time, or dilute the brew more when serving.
After steeping, pour the mixture through a fine mesh strainer lined with cheesecloth, a paper coffee filter, or a dedicated cold brew filter bag. Filter twice for a cleaner, sediment-free result.
Cold brew concentrate is significantly stronger than a typical cup of drip coffee — often 2 to 3 times the caffeine concentration per milliliter. Ready-to-drink cold brew at 1:14–1:17 is comparable in caffeine to standard hot coffee.
Roboculator Team
The Roboculator Team explains calculations, planning tools, and practical formulas in clear language for real-life situations.
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