Coffee-to-Water Ratio Calculator
Find the ideal amount of coffee grounds and water for your preferred brewing method. Supports drip, pour-over, French press, espresso, and cold brew with standard ratio recommendations.
Great coffee is a math problem most people solve by intuition and accept mediocre results. The Specialty Coffee Association (SCA) "golden ratio" is 1:18 by weight — one gram of dry coffee per 18 grams of water — and once you switch to weighing grounds and water instead of scooping, your coffee gets noticeably better with no other change. Most home brewers run too lean (1:20 to 1:25), producing weak, sour coffee they then over-extract by brewing longer, which adds bitterness without adding strength.
This calculator converts between cups, ounces, and grams to give you the exact dose of grounds and water for any brew method. The default settings target the SCA gold-cup range (1:17 to 1:18), but you can dial up to a 1:13 espresso ratio or down to a 1:6 cold brew concentrate. The math holds across methods because the ratio describes how much soluble material is available to extract; the brew method (drip, pour-over, immersion, espresso) controls how much actually gets extracted.
A few practical notes. First, weigh both coffee and water — a kitchen scale that reads to 0.1g is the single biggest equipment upgrade for home coffee. Second, "ounces" in coffee marketing are always fluid ounces (volume), but ratios are mass-based. One fl oz of water weighs ~30 g, close enough. Third, cold brew ratios are deliberately concentrated because the finished concentrate gets diluted 1:1 to 1:2 with water or milk before drinking.
Inputs
Results
Coffee
44.4g (8.9 tbsp)
Water
710 ml (24 oz)
Ratio
1:16.0
Brew Details
| Measurement | Amount |
|---|---|
| Coffee (grams) | 44.4 |
| Coffee (tablespoons) | 8.9 |
| Water (ml) | 710 |
| Water (fl oz) | 24.0 |
| Brew Ratio | 1:16.0 |
Formula
How to use this calculator
- Pick your brew method. Each has a default ratio range; cold brew especially varies widely depending on whether you want concentrate or ready-to-drink.
- Enter desired output. "Cups" on the calculator means 6-oz coffee cups (the carafe-cup standard); adjust cup size if you mean mugs (10–14 oz).
- The calculator outputs grams of coffee, grams (and oz/ml) of water, and an approximate tablespoon count.
- Weigh the coffee on a scale. Volumetric measures vary too much between dark roast (denser) and light roast (lighter).
- Use filtered water at 195–205°F for hot methods, room temp or cold for cold brew.
- Taste and adjust. Weak/sour → use more coffee (lower ratio number). Bitter → use less coffee (higher ratio) or grind coarser.
Worked examples
Drip coffee for a household of four
**Scenario:** Each person wants a "mug" (10 oz) of medium-strength drip coffee in the morning. **Calculation:** 4 mugs × 10 oz = 40 fl oz water = ~1184 g. At 1:17 medium ratio: 1184 / 17 = 70 g coffee = ~14 level tablespoons. Set up: weigh 70 g of beans, grind to medium, pour into drip basket, fill reservoir to the "40 oz" mark. **Result:** 70 g coffee + ~1.2 L water yields four 10-oz mugs at SCA gold-cup strength. If your drip machine's "10-cup" line is misleading (often calibrated to 5-oz cups), use a real cup or weigh water directly into the reservoir.
Pour-over for one (V60)
**Scenario:** Single 12-oz mug of pour-over coffee. Want clean, bright flavor. **Calculation:** 12 fl oz = ~355 g water. At 1:16 ratio: 355 / 16 = 22 g coffee, medium-fine grind. Bloom: pour 50 g water on grounds, wait 30 s. Then pour in slow spirals to total 355 g over 2:30–3:00 total brew time. **Result:** 22 g coffee in V60 with 355 g water at 200°F, brewed over ~3 minutes. Adjust grind finer if it brews too fast (under 2:30); coarser if it stalls past 3:30. Total prep time including bloom is about 4 minutes.
Cold brew concentrate for the week
**Scenario:** Make a week's worth of cold brew concentrate to dilute and serve daily. **Calculation:** Want roughly 1.5 L of concentrate, used 1:1 with water/milk for ~3 L of finished coffee = 6–7 servings. At 1:5 ratio: 1500 g water / 5 = 300 g coffee. Grind coarse, combine, steep 14 hours at room temp, filter through cheesecloth and paper filter. **Result:** 300 g coffee + 1.5 L cold water = ~1.5 L concentrate after filtering. Refrigerated, the concentrate keeps 7–10 days. Serve over ice with 1:1 water, milk, or oat milk dilution. Adjust to 1:7 if you prefer a less intense concentrate.
When to use this calculator
**Use coffee ratio math when:**
- **Switching brew methods**: dialing in a new V60 or French press is mostly about finding your ratio sweet spot, then tweaking grind. - **Buying new coffee**: different roasts and origins respond to slightly different ratios. Light Ethiopian beans often want 1:16; dark Brazilian roasts can take 1:18 without going thin. - **Brewing for guests**: making 8 cups when you usually make 2 is where eyeballing fails. Always weigh for bigger brews. - **Diagnosing weak or bitter coffee**: weak/sour usually means under-dosed (ratio too high) or under-extracted (grind too coarse). Bitter means over-extracted (grind too fine, too long, water too hot, or ratio too low). - **Reducing waste and cost**: precise dosing means no more "throwing out half a pot." A typical home reduces beans consumed by 10–15% just by switching from scoop to scale. - **Replicating a great cup**: the best home coffee experiences are reproducible only if you wrote down the ratio. "I used about a scoop and some" isn't reproducible.
**SCA Gold Cup standard:**
- Total dissolved solids (TDS) target: 1.15–1.35% - Extraction yield target: 18–22% - Brew strength target: 1.15–1.55% (Specialty Coffee Association of America standard) - Coffee:water ratio: 55 g/L ± 10% (= ratios 1:18 to 1:16)
This is the target that pro tasters and competition judges use. Home methods can hit it consistently with a scale, the right grind, and the right water temp.
**When to deviate from SCA "golden ratio":**
- **Iced coffee (hot-brewed, poured over ice)**: dose 50% more coffee because the ice dilutes. - **Office or hotel "weak" coffee preferences**: 1:20 instead of 1:17. - **Espresso/concentrate methods**: ratios are intentionally aggressive because the output is small. - **Specialty drinks (lattes, cappuccinos)**: pull a stronger shot (1:1.5 ristretto) so milk doesn't flatten the coffee flavor.
Common mistakes to avoid
- Measuring coffee by tablespoons. The actual mass varies 15–25% between coarse and fine grinds and between light and dark roasts.
- Using the "cup" line on your drip machine as a real cup. Most are calibrated to 5-oz "carafe cups," not 8-oz measuring cups or 10–14-oz mugs.
- Brewing too small a batch on a 12-cup drip machine. Most drip baskets need at least 6 cups' worth of water flow to extract evenly.
- Skipping the bloom on pour-over and drip. The 30–45 second bloom releases CO₂ from fresh grounds; without it, water channels around the bed and extraction is uneven.
- Using boiling water (212°F). The SCA target is 195–205°F. Boiling water over-extracts and brings out bitterness.
- Brewing with old, stale beans. Coffee tastes best 5–14 days after roast. After 30 days, even a perfect ratio can't save it.
- Forgetting that espresso ratios are inverted. Espresso 1:2 is dose:yield (e.g., 18g grounds → 36g liquid out), not coffee:water like drip.