Coffee Calculator

Calculate coffee grounds and water for the perfect brew based on the number of cups, preferred strength, and brewing method.

COFFEE GROUNDS
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Water Needed
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Tablespoons
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Coffee:Water Ratio
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Est. Caffeine
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Coffee Brewing Basics

The perfect cup of coffee depends on the right balance between coffee grounds and water. The Specialty Coffee Association (SCA) recommends a golden ratio of approximately 1:15 to 1:18 (coffee to water by weight) for most brewing methods. This means for every gram of coffee, you should use 15-18 grams (or milliliters) of water. Adjusting this ratio up or down controls the strength and body of your brew.

Beyond the ratio, water temperature plays a critical role. The ideal brewing temperature is between 195 and 205 degrees Fahrenheit (90-96 degrees Celsius). Water that is too hot over-extracts the coffee, leading to bitter flavors, while water that is too cool under-extracts, resulting in a sour, weak cup. Grind size must also match your brewing method: finer grinds for shorter contact time (espresso) and coarser grinds for longer steeping (French press).

The Golden Ratio

Coffee (g) = Water (ml) ÷ Ratio
Standard Cup = 6 oz (177 ml) of water

The SCA golden ratio is 1:16.7 (about 10g of coffee per 6 oz cup). For a stronger brew, decrease the ratio to 1:14 or 1:13. For lighter coffee, increase it to 1:18 or 1:20. One level tablespoon of ground coffee weighs approximately 5 grams, so a standard cup uses about 2 tablespoons.

Brewing Methods Guide

MethodRatio (coffee:water)Grind SizeBrew TimeWater Temp
Drip / Auto1:16Medium5-6 min200°F
Pour Over1:15Medium-Fine3-4 min200°F
French Press1:15Coarse4 min200°F
Espresso1:2Very Fine25-30 sec200°F
AeroPress1:12Fine-Medium1-2 min185°F
Moka Pot1:7Fine4-5 minStovetop

Grind Size Guide

  • Extra Coarse (cold brew): Resembles peppercorns. Steep 12-24 hours.
  • Coarse (French press): Resembles sea salt. 4-minute steep.
  • Medium-Coarse (Chemex): Between sea salt and sand.
  • Medium (drip): Resembles sand. Standard auto-drip grind.
  • Medium-Fine (pour over): Finer than sand, coarser than sugar.
  • Fine (espresso, Moka pot): Resembles table salt or sugar.
  • Extra Fine (Turkish): Resembles flour or powdered sugar.

Frequently Asked Questions

How much coffee do I need for 12 cups?

For 12 standard 6-oz cups (72 oz total water), you need approximately 120 grams or 24 tablespoons (about 3/4 cup) of ground coffee at a medium strength ratio of 1:16. For stronger coffee, use up to 135 grams (27 tablespoons). Most 12-cup coffee makers actually brew about 60 oz, so check your machine's cup size definition.

Does brewing method affect caffeine content?

Yes, significantly. A standard 8-oz drip coffee contains about 95 mg of caffeine. A single espresso shot (1 oz) has about 63 mg but is much more concentrated. French press coffee tends to have slightly more caffeine than drip because of the longer steep time and coarser filter allowing more oils and compounds through. Cold brew concentrate can contain 200+ mg per 8 oz due to the extended steeping time.

Why does my coffee taste bitter?

Bitterness usually comes from over-extraction. Common causes include water that is too hot (over 205 degrees Fahrenheit), a grind that is too fine for your method, or brewing for too long. Try reducing brew time, using slightly coarser grounds, or lowering water temperature by 5 degrees. Also ensure your equipment is clean, as old coffee oils can become rancid and contribute bitter off-flavors.