Coffee Ratio Calculator

Pick a brew method, set how many cups you are making, and choose a strength. The calculator returns the ground coffee to weigh out in grams, the water in milliliters, and the ratio it used to connect them, written the way brewers write it: 1:16 means one gram of coffee for every sixteen grams of water. The grams figure is the one to act on, because the dose decides how the cup tastes and a kitchen scale can pin it down precisely. In espresso mode the inputs switch to shots and the water line changes meaning, since espresso ratios compare the dose with the liquid in the cup rather than the water in the tank.

How the calculation works

Every method except espresso follows the same two steps. Water is the cup count multiplied by a 240 ml cup, and coffee is that water divided by the brew ratio:

water = cups × 240

coffee = water ÷ ratio

A milliliter of water weighs one gram for kitchen purposes, so the division lands directly in grams whether you measure water by volume or on a scale. The strength setting does not alter your grind or your pour; it swaps the ratio. Pour-over runs 1:16 balanced, 1:17 mild and 1:15 strong. French press runs 1:14, 1:15 and 1:13. Cold brew concentrate is far tighter at 1:4.5, 1:5 and 1:4, because the jar you brew is meant to be cut with water or milk before drinking. Espresso ignores cups entirely: the dose is 9 g per shot and the beverage weight is twice the dose, a 1:2 ratio measured into and out of the portafilter.

A worked example

With the defaults, pour-over at two cups and balanced strength, the water is 2 × 240 = 480 ml. At 1:16 the coffee is 480 ÷ 16 = 30.0 g. Strong swaps the ratio to 1:15 for 480 ÷ 15 = 32.0 g, mild at 1:17 drops the dose to about 28.2 g, and the water never moves. A single balanced cup of French press works out to 240 ÷ 14 ≈ 17.1 g, and a 350 ml mug of it needs 350 ÷ 14 = 25 g. Brewing a full liter at the Specialty Coffee Association's standard of 55 g per liter takes exactly 55 g, and the older Golden Cup tolerance of plus or minus 10 percent allows 49.5 to 60.5 g. Fifty-five grams per liter is roughly 1:18, so the standard sits slightly milder than the 1:15 to 1:17 window most modern pour-over recipes quote.

The chart behind the golden cup

The idea that a coffee ratio could be standardized at all is a mid-century American project. By the early 1950s the National Coffee Association, representing roasters, and the Pan American Coffee Bureau, representing growers, had joined forces to found the Coffee Brewing Institute, an attempt to put brewing on a scientific footing. The research associated with the institute was led by Ernest E. Lockhart, a scientist at MIT, and its lasting artifact is the Coffee Brewing Control Chart: brew strength, measured as total dissolved solids, plotted against extraction yield, the percentage of the grounds' mass that dissolves into the drink, with a diagonal line for each brew ratio crossing the field. The box in the middle, where strength falls between 1.15 and 1.35 percent and extraction between 18 and 22 percent, became known as the golden cup, and Lockhart published his findings in 1957. The recommendations rested on preference surveys of American drinkers of its era, a record of what one population liked at one moment rather than a law of nature. Even the paternity is blurry: Coffee Chronicler, citing David Walsh of Marco Beverage Systems, reports that the research behind the 18 to 22 percent guideline came from the Midwest Research Institute in 1957 and that its exact methodology remains elusive, so the fair credit is research associated with Lockhart and the institute rather than one man's experiments.

The numbers outlived the institute. The Specialty Coffee Association of America carried them forward as its Golden Cup Standard, 55 g of coffee per liter of water with a tolerance of plus or minus 10 percent, strength of 1.15 to 1.35 percent, extraction of 18 to 22 percent and water at 200 °F give or take 5, last revising the document on December 23, 2015 and building its Certified Home Brewer program on it. In 2021 the merged association reissued the requirements as SCA Standard 310-2021 for home coffee brewers, published through the SCA standards program. The 2021 text keeps 55 g per kilogram of water as the standard brew ratio but widens the target strength to 1.15 to 1.55 percent and asks that the brewing slurry reach 90 to 96 °C early in the brew; the 10 percent tolerance belongs to the older Golden Cup document, not to the 2021 standard. William Ristenpart of the University of California, Davis is listed among the 2021 contributors, and in 2023 a UC Davis Coffee Center team of Guinard, Frost, Batali, Cotter, Lim and Ristenpart published a rebuilt control chart in the Journal of Food Science from modern sensory panels and consumer testing. It found preferences following more complicated trends than the classic chart implied, with drinkers splitting into two clusters with different likes and dislikes, a quiet admission seventy years on that no single box suits everyone.

Why the ratio depends on the method

Only the 55 g per liter figure and the golden cup windows carry a standards body's name; the method presets are conventions of the specialty trade and should be read as starting points. Pour-over and drip guides cluster between 1:15 and 1:17, with 1:16 called the standard pour-over ratio in one retailer's guide, InstaCuppa's, and French press guides sit between 1:12 and 1:15. Espresso is the outlier because its ratio measures something else entirely: dose in against beverage out, both in grams. Trade references from Clive Coffee, Seattle Coffee Gear and La Marzocco put a normale at roughly 1:1.5 to 1:2.5, commonly 18 g pulled to 36 g in 25 to 30 seconds, with ristretto at 1:1 to 1:1.5 and lungo at 1:3 to 1:4. Writing espresso as coffee-to-water would mislead anyone comparing it with a drip ratio; the second number is always the weight in the cup.

Cold brew looks extravagant only until the dilution step is counted. Toddy, whose classic method the company dates to 1964, publishes a recipe of 340 g of coarse-ground coffee steeped in 1.9 liters of room-temperature water for 8 to 24 hours, roughly 1:5.6, then served as one part concentrate to two parts water or milk. Published concentrate recipes range from about 1:4 to 1:8, and this calculator's presets of 1:4 to 1:5 sit at the stronger end of that spread, so the mild setting is the one closest to Toddy's own card.

A cup is not a mug

The word cup causes more failed coffee than any ratio. The cup in this calculator is 240 ml, and a balanced pour-over cup therefore takes 240 ÷ 16 = 15 g of coffee. A mug usually holds more, 350 ml being common, so filling one at 1:16 needs about 22 g, half again the dose. Carafe markings go the other way: the cup lines printed on a drip brewer are smaller than a measuring cup, so a machine sold as ten cups fills fewer mugs than its name promises. Before trusting any dose, find out how many milliliters the cup in question means; the arithmetic is indifferent to what the vessel is called.

Assumptions and editorial choices

The ratios here are editorial midpoints of the trade ranges above, not prescriptions: 1:17, 1:16 and 1:15 for mild, balanced and strong pour-over; 1:15, 1:14 and 1:13 for French press; 1:5, 1:4.5 and 1:4 for cold brew concentrate before dilution. A cup is fixed at 240 ml, and one milliliter of water is treated as one gram, so weight and volume figures are interchangeable. Espresso uses a fixed 1:2 dose-to-beverage ratio, and a shot is defined editorially as 9 g of coffee yielding 18 g of espresso, chosen so that the default two shots reproduce the trade's standard example of 18 g in and 36 g out; in espresso mode the water line therefore shows the weight of liquid espresso read as milliliters, not the water in the machine's tank. Coffee is displayed to one decimal and water to the nearest milliliter. The 2023 UC Davis finding of two distinct preference clusters is a good reason to nudge the ratio half a point at a time until the cup tastes like yours.

Frequently asked questions

What is the golden ratio for coffee to water?

The Specialty Coffee Association's standard brew ratio is 55 grams of coffee per liter of water, which works out to roughly 1:18. The older SCAA Golden Cup Standard allowed a tolerance of plus or minus 10 percent, so anywhere from 49.5 to 60.5 grams per liter. Most modern pour-over recipes run a little stronger than that, typically between 1:15 and 1:17.

How much coffee do I need for one mug?

Divide the mug's volume in milliliters by your ratio. A large 350 ml mug at 1:16 needs about 22 grams of ground coffee, while this calculator's 240 ml cup needs 15 grams. Watch the cup markings on a drip brewer's carafe too, because they are smaller than a measuring cup, so a ten-cup machine fills fewer than ten mugs.

Why is the espresso ratio 1:2 when drip coffee is 1:16?

The two numbers measure different things. An espresso ratio compares the dry dose with the weight of liquid espresso in the cup, so 18 grams of grounds pulled to 36 grams of espresso is 1:2, while a drip ratio compares coffee with brew water. Trade guides from Clive Coffee, Seattle Coffee Gear and La Marzocco describe a normale as roughly 1:1.5 to 1:2.5, with 18 grams in and 36 grams out as the standard example.

Why does cold brew use so much more coffee?

Cold brew is normally made as a concentrate and diluted before drinking. Toddy's official recipe steeps 340 grams of coarse-ground coffee in 1.9 liters of room-temperature water for 8 to 24 hours, roughly 1:5.6, then serves one part concentrate with two parts water or milk. Most of the water is added at serving time rather than in the steep, which is why the brewing ratio looks so heavy.

Can I measure brew water with a kitchen scale?

Yes. A milliliter of water weighs one gram for kitchen purposes, so ratios work identically by weight: a 1:16 brew takes 480 grams of water for 30 grams of coffee. Weighing is more repeatable than volume marks, and it is how this calculator treats water, converting cups to milliliters and reading those as grams.

What do TDS and extraction yield mean for coffee?

Total dissolved solids measures strength, the share of the liquid that is dissolved coffee, and the classic Golden Cup window is 1.15 to 1.35 percent. Extraction yield measures how much of the grounds' mass ended up in the drink, with 18 to 22 percent the traditional target. They are the two axes of the Coffee Brewing Control Chart developed in the 1950s and redrawn from modern consumer data by UC Davis researchers in 2023.