Quickly calculate the exact amount of water needed for your coffee beans based on your preferred brew ratio.
Last updated: March 2026
The brew ratio is the single most important variable in coffee brewing. It determines the strength and extraction of your cup. A 1:15 ratio means for every 1 gram of coffee, you use 15 grams of water. This results in a more concentrated brew with a heavier body.
A 1:17 ratio is more common for pour-over methods, resulting in a cleaner, more delicate cup that highlights the nuanced flavors of the beans. By weighing your ingredients and sticking to a consistent ratio, you can easily troubleshoot and refine your brewing process.
Start with whole coffee beans (not pre-ground). Use a digital kitchen scale for accuracy—place a small bowl on the scale, zero it, then add your beans. Most home brewers start with 25–40g of beans for a single cup or serving.
Enter your desired brew ratio (1:x format). The 1:16 SCA Golden Ratio is the industry standard—it balances extraction rate and flavor. Adjust to preference: 1:14–1:15 for a stronger, bolder cup; 1:17–1:18 for a lighter, more delicate brew.
The calculator instantly shows the exact water weight needed (in both grams and ml). Water and coffee weigh roughly the same (1g ≈ 1ml), so 480g of water ≈ 480ml. This is your target brew weight.
Water temperature is critical. Too hot (>205°F) over-extracts and burns coffee; too cool (<195°F) under-extracts and tastes sour. Most kettles reach 200–205°F after boiling and a 30-second cool-down. Use a thermometer if precision matters to you.
Grind your beans to match your brewing method (coarse for French press, medium for drip, fine for espresso). Add grounds and water per the calculator's amounts, brew for 3–5 minutes depending on method, then pour and savor your perfectly balanced cup.
You wake up Sunday morning and want a rich, full-bodied cup using the Chemex method. You prefer slightly stronger coffee, so you'll use a 1:15 ratio instead of the standard 1:16.
You grind your 40g of fresh beans to medium-fine, set your Chemex, and pour the 600ml of 200°F water in slow circular motions over 4 minutes. The result: a smooth, full-bodied cup with pronounced origin flavors.
The 1:16 ratio is the industry standard for most brewing methods, providing a balanced cup. However, personal preference plays a big role. Start with 1:16 and adjust based on taste—1:15 for a stronger brew, 1:17 for a lighter one.
Coffee density varies by origin, roast, grind size, and grinding consistency. A volume scoop of light roast weighs less than the same scoop of dark roast. Digital scales ($15-40) ensure precise, repeatable results. Even a small kitchen scale transforms brewing consistency.
The 1:16 ratio works universally for drip, pour-over, Aeropress, and Chemex. French press typically uses slightly less water (1:15), while espresso uses completely different measurements (measured in grams per shot). This calculator applies to immersion and percolation methods.
This calculator measures whole beans by weight before grinding. The ratio stays the same whether you grind coarse or fine—but grind size affects extraction time. Finer grinds extract faster, so you might use slightly higher ratios to avoid over-extraction.
Yes. Use filtered or spring water, not distilled or tap with chlorine. Water hardness (mineral content) affects extraction. Too soft = under-extraction, too hard = bitter. Ideal water has some minerals but isn't heavily chlorinated. Most tap water filtered works well.
Yes, absolutely. The ratio stays constant regardless of scale. Brewing 30g coffee to 480g water or 100g to 1600g follows the same 1:16 math. Scale up or down while maintaining the ratio for consistent results at any volume.
Aim for ±1% accuracy (so 30g ±0.3g). Most scales are ±1g at best. Being within 5-10% is fine for casual brewing. As you dial it in, tighter precision helps identify your preferred flavor profile.
Check grind size (too fine = bitter, too coarse = weak), water temperature (195-205°F is ideal), brewing time, bean freshness (use within 2 weeks of roasting), and water quality. Ratio is one variable among many—dial in other factors too for the best cup.