Coffee Ratio Calculator

A coffee ratio calculator turns a brew ratio into amounts you can measure. At 1:16, 12 fl oz (355 mL) of water needs 22.2 g of ground coffee, about 2.2 level scoops; a 34 fl oz French press at 1:14 needs 71.8 g. For general kitchen conversions such as cups to grams of flour, the Cooking Converter is the better tool. Use this page when the question is how much coffee, how much water, or how much caffeine.

The coffee ratio formula

A ratio such as 1:16 means 1 part ground coffee to 16 parts water by weight. Because 1 milliliter of water weighs very nearly 1 gram, the water side can be read in grams or milliliters; the coffee is the part worth weighing.

The third line accounts for the water left in the spent grounds, roughly twice the weight of the coffee, so you always pour out less than you put in. Espresso is the exception: its ratio runs from dose to yield, as shown further down.

Worked example: a 12 fl oz pour over at 1:16

One US fluid ounce is 29.5735 mL, so 12 fl oz of water is 354.9 mL, or 354.9 g:

That is 0.78 oz by weight, or 2.2 scoops of 10 g. The grounds keep about 2 × 22.2 = 44.4 g of water, so the cup holds about 311 mL (10.5 fl oz). Caffeine: 22.2 g × 7.5 to 10 mg = 166 to 222 mg, or 42% to 55% of the FDA's 400 mg daily reference. The calculator opens on exactly this case.

Worked example: a 34 oz French press at 1:14

A large French press holds 34 fl oz, which is 1,005.5 mL. French press runs stronger than drip, so use 1:14:

That is 2.53 oz, about 7.2 scoops of coarse coffee. After the grounds take about 143.6 g of water, roughly 862 mL (29.1 fl oz) reaches the cups, about 3.6 servings of 8 fl oz. The pot carries an estimated 539 to 718 mg of caffeine, 148 to 197 mg per serving, so it is a pot to share.

Starting ratios by brew method

Each method extracts at a different speed, so each has its own range. The National Coffee Association's brewing guides list 1:13 to 1:16 for pour over, 1:10 to 1:16 for French press, 1:4 to 1:5 for cold brew concentrate and 1:2 for espresso; the ranges below add common home recipes.

In a moka pot the basket fixes the dose, so the water you add sets the ratio. A 2022 study in the journal Foods brewed its moka coffee at 76 g per liter (about 1:13) and its drip coffee at 50 g per liter (1:20).

Grams of coffee for common water amounts

Every value is water ÷ ratio, rounded to 0.1 g, matching the calculator. A 16 fl oz travel mug takes 39.4 g at 1:12 but 26.3 g at 1:18: half again as much coffee for the stronger brew.

Coffee maker cups are not measuring cups

A US measuring cup is exactly 8 fluid ounces under NIST Handbook 44, about 236.6 mL, and nutrition labels round it to 240 mL under the FDA's labeling rule. Coffee makers use neither: carafe markings usually count "cups" of about 5 or 6 fl oz, so a 12-cup machine holds 60 to 72 fl oz, not 96. Measure your carafe once and pick the matching unit. The table assumes 5 fl oz cups.

With 6 fl oz cups, multiply by 1.2: 12 cups becomes 72 fl oz of water and 133.1 g of coffee at 1:16.

Espresso and cold brew: two special cases

Espresso runs from dose to yield. Put 18 g of finely ground coffee in the basket, stop at 36 g of liquid in the cup, and you have a 1:2 shot, the ratio in the NCA's espresso guide, in 20 to 30 seconds. Yields below are dose × ratio.

Cold brew is the other extreme: coarse coffee steeps in cold or room-temperature water for about 12 hours at a strong ratio, then gets diluted. Worked example: 200 g of coffee at 1:5 needs 1,000 mL of water. The grounds keep about 400 g, leaving roughly 600 mL (20.3 fl oz) of concentrate; diluted 1:1 that is 1,200 mL, about 5.1 servings. The estimate is 1,500 to 2,000 mg of caffeine for the batch, 296 to 394 mg per 8 fl oz of the diluted drink. Wet grounds hold back some caffeine, so real values are likely lower, but concentrate is not a drink to have straight.

Scoops, tablespoons and the golden ratio

Tablespoon recipes trace back to the NCA's golden ratio: 1 to 2 tablespoons of ground coffee for every 6 ounces of water. A US tablespoon is half a fluid ounce (about 14.8 mL); level with ground coffee it weighs roughly 5 g, and a standard scoop holds 2 tablespoons, about 10 g. So 2 tablespoons per 6 fl oz (177.4 mL) is about 1:18, close to modern drip recipes, while 1 tablespoon is about 1:35, which most people find weak. Weigh one level scoop of your coffee and enter it in the calculator.

How much caffeine is in your brew

The FDA cites 400 mg a day for most healthy adults as an amount not generally associated with negative effects, about two to three 12 fl oz cups of coffee. It lists 113 to 247 mg for a 12 fl oz cup of regular brewed coffee and 2 to 15 mg per 8 fl oz for decaf. NIH's MedlinePlus lists 75 to 100 mg for a 6-ounce cup and about 40 mg for a 1-ounce espresso.

Caffeine comes from the grounds, so this calculator works per gram. If that 6-ounce cup is brewed with the golden ratio's 2 tablespoons (about 10 g), 75 to 100 mg means 7.5 to 10 mg per gram, the range used here. A 12 fl oz cup at 1:16 to 1:18 uses 19.7 to 22.2 g, giving 148 to 222 mg, inside the FDA's range. Bean, roast and method still move the real value. If you are pregnant or breastfeeding, ask a health care provider about limits.

How to use this calculator and who it is for

Pick a brew method to load its starting ratio, then choose what you know. My water takes fl oz, mL, grams, liters, US cups or machine cups and returns the coffee in grams, ounces, scoops and tablespoons. My coffee works backward: the last 30 g in the bag needs 480 mL of water at 1:16. Changing a unit converts the amount you typed, so 12 fl oz becomes 354.9 mL rather than 12 mL. Fine-tune with the slider, set your scoop weight, and choose Decaf or a cold brew dilution if they apply. It suits home brewers moving from scoops to a scale, offices filling a full carafe, and baristas scaling an espresso recipe.

Key terms

• Brew ratio: coffee to water by weight, written 1:16; a smaller second number means stronger coffee.
• Dose and yield: the dry coffee you use and the liquid that ends up in the cup.
• Bloom: the first small pour in a pour over; its water counts toward the total.
• Extraction: how much of the coffee dissolves, set mostly by grind, time and temperature.
• Machine cup: the 5 or 6 fl oz "cup" marked on coffee makers.

What changes the result, and tips for dialing in

• The ratio sets strength. Going from 1:16 to 1:14 adds about 14% more coffee for the same water.
• Grind and time set extraction. Bitter or harsh: grind coarser or brew shorter. Sour or thin: finer or longer. Change the ratio only after that.
• Temperature matters for hot methods. The NCA's pour-over and French press guides give 93 ± 3°C, roughly 195 to 205°F.
• Change one thing at a time and write down the dose, water, grind and time of a cup you liked.

Limitations and related calculators

The calculator counts 1 mL of water as 1 g and assumes the grounds keep twice their weight in water; real retention varies, and moka pots leave water in the base. Caffeine is estimated, not measured, and robusta-heavy blends can carry more. For other ingredients use the Cooking Converter, for liters and gallons the Unit Converter, to scale any recipe the Ratio Calculator, and to express 1:16 as a share (6.25% of the water) the Percentage Calculator.

Sources

• U.S. Food and Drug Administration, Spilling the Beans: How Much Caffeine Is Too Much? (current as of August 28, 2024): 400 mg reference, 113 to 247 mg per 12 fl oz, decaf, 1,200 mg.
• NIH National Library of Medicine, MedlinePlus, Caffeine in the diet (reviewed April 1, 2025): 75 to 100 mg per 6-ounce cup, 40 mg per 1-ounce espresso.
• National Coffee Association brewing guides: drip, pour over, French press, cold brew, espresso.
• NIST, Handbook 44 (2026), Appendix C: cup, fluid ounce, tablespoon and avoirdupois ounce.
• 21 CFR 101.9(b)(5)(viii): a nutrition-labeling cup means 240 mL.
• Vezzulli F., Rocchetti G., Lambri M., Lucini L., extraction methods and coffee beverages, Foods 2022;11(6):807: moka and filter brew ratios.