Coffee to Water Ratio CalculatorPerfect Brew for Pour-Over, Drip, French Press & Cold Brew
Choose your brew method and how many cups you’re making to get the exact coffee and water in grams, tablespoons, mL and ounces, plus grind, brew time, water temperature and an estimate of the caffeine.
Built & pharmacist-reviewed by Manzoor Ahmad, Pharmacist & Calculator Developer · Updated
Ratios follow Specialty Coffee Association brewing standards. Caffeine limits follow the FDA.
What is the right coffee to water ratio?
Use 1 g of coffee for every 15–18 g of water (1:15 to 1:18). For one 8 oz cup that’s about 15 g of coffee, roughly 3 tablespoons. Pour-over works best around 1:16, drip machines 1:17, French press 1:15, cold brew 1:8, and espresso 1:2 by weight. Use a lower ratio, such as 1:15, for stronger coffee.
Your brew
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Grind & brew guide
Coffee to water ratio by brew method
Grams of coffee per 8 fl oz (240 mL) cup. The Specialty Coffee Association “golden cup” standard is about 1:18 (55 g per litre).
| Method | Ratio | Coffee per 8 oz cup | Per 1 litre |
|---|---|---|---|
| Pour-over / V60 | 1:15–1:17 | 14–16 g (≈ 3 tbsp) | 60–67 g |
| Drip machine | 1:16–1:18 | 13–15 g | 55–63 g |
| French press | 1:12–1:15 | 16–20 g | 67–83 g |
| AeroPress | 1:11–1:15 | 16–22 g | 67–91 g |
| Cold brew (ready) | 1:8 | 30 g | 125 g |
| Espresso | 1:2 (by weight) | 18 g in → 36 g out | — |
How the brew maths works
Caffeine is an estimate. Arabica beans contain about 1.2% caffeine, Robusta about 2.2%, and extraction depends on grind, time and temperature.
4 cups of drip coffee at 1:17
- Water: 4 × 240 = 960 mL
- Coffee: 960 ÷ 17 = 56.5 g, about 10.7 tbsp
- Caffeine: 56.5 × 11 ≈ 620 mg in total, about 155 mg per cup
- For stronger coffee at 1:15, use 64 g.
Coffee and your medicines
Coffee taken at the same time as levothyroxine can cut its absorption by up to 30%. Wait 30–60 minutes after your thyroid tablet. Ciprofloxacin and fluvoxamine slow caffeine clearance a lot, so the same cup can feel like three. Coffee also reduces iron absorption if taken with iron tablets or iron-rich meals. Space them by about 1 hour.
Limits: healthy adults up to about 400 mg a day, and up to 200 mg during pregnancy. If you have arrhythmias, anxiety disorders or insomnia, less is usually better. Our Health Calculators include a caffeine half-life tool that shows how long caffeine stays in your system.
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Coffee to Water Ratio calculator FAQs
Most brewing guides recommend 1:15 to 1:18, meaning 1 g of coffee for every 15–18 g (mL) of water. The Specialty Coffee Association’s golden cup standard is about 55 g of coffee per litre (≈ 1:18). Use 1:15 for stronger coffee.
For an 8 oz (240 mL) cup at 1:16, use about 15 g, which is roughly 2½–3 level tablespoons of ground coffee. The classic ‘2 tablespoons per 6 oz’ rule works out to about 1:18.
For a 12-cup drip machine, note that machine ‘cups’ are usually 5–6 oz, so the carafe holds about 60 oz (1.8 L). At 1:17 that needs about 105 g of coffee, or roughly 20 tablespoons.
Use 1:12 to 1:15. For a 1 L press, that’s 67–83 g of coarse-ground coffee. Steep for 4 minutes, then press slowly.
Use 1:8 for ready-to-drink cold brew and 1:4 to 1:5 for concentrate that you dilute 1:1. Steep coarse grounds for 12–20 hours in the fridge, then strain.
An 8 oz cup of drip coffee has about 80–150 mg of caffeine. A single espresso shot has about 60–75 mg. Cold brew can contain 150–250 mg per serving, depending on the ratio and dilution.
Manzoor Ahmad
Pharmacist · Supplement & Nutrition Writer (9+ yrs) · Calculator Developer (13+ yrs)
I’m a pharmacist and DexoCalc’s developer. Coffee comes up at the counter more than you’d think, because of how it interacts with thyroid medicine, antibiotics and iron. So alongside a precise brew ratio, this calculator estimates caffeine and flags when a pot pushes past safe daily limits.
References
- Specialty Coffee Association. Protocols & Best Practices.
- FDA. Spilling the Beans: How Much Caffeine Is Too Much?
- Benvenga S, et al. Altered intestinal absorption of L-thyroxine caused by coffee. Thyroid. 2008;18(3):293–301. PubMed
- ACOG. Moderate Caffeine Consumption During Pregnancy.
Note: Caffeine values are estimates and vary with bean, roast, grind and brew time. This is not medical advice. If you’re pregnant or take interacting medicines, ask your pharmacist about safe limits.