Coffee to Water Ratio Calculator
Work out how much coffee to use for any amount of water, or how much water for a given dose, at any brew ratio.
What you need
31.3g
Coffee — Weigh it. Beans vary enough in density that scoops are not repeatable.
- Coffee in ounces
- 1.1 oz
- Coffee in tablespoons
- 5.9 tbsp
- Water
- 500 ml
- Water in fluid ounces
- 16.9 fl oz
- Coffee maker cups
- 3.4
Approximate — a tablespoon of coffee varies with grind and roast.
At the 5 fl oz cup your machine's markings use, not an 8 fl oz measuring cup.
Guide figures. Ingredient weights, pan sizes and cooking times all vary — see the assumptions below for the ones used.
Shop this project
A ratio is only repeatable if the grind and the dose are. These are the two things worth owning before a better brewer. Quantities come straight from your calculation above — check them against your supplier's pack sizes before ordering.
Tools & equipment
Coffee scale with timer
0.1 g resolution and a built-in timer — the two things a kitchen scale usually lacks.
Burr grinder
A blade grinder produces a mix of dust and boulders, which over- and under-extract at the same time.
French press
Immersion brewing, so the ratio does the work rather than your pouring technique.
Pour-over brewer
Affiliate disclosure: some links above are affiliate links. We may earn a commission if you buy through them, at no additional cost to you. As an Amazon Associate we earn from qualifying purchases. Read the full disclosure. We have not tested these specific products and no retailer endorses this site.
How to use the coffee to water ratio calculator
Coffee strength is a ratio of coffee weight to water weight, written as 1:16 or similar. Because a millilitre of water weighs a gram, the arithmetic is simple once you know the ratio you want — and knowing it is what makes a brew repeatable instead of a guess. Work from whichever you know, the water or the coffee.
Why a ratio beats a scoop
A scoop measures volume, and coffee's volume has very little to do with how much coffee is in it. A dark roast is less dense than a light one, a coarse grind traps more air than a fine one, and a bean two weeks past roast has lost gas and settled. Two level scoops can differ by a quarter in weight.
A ratio by weight removes all of that. It also makes a result you liked reproducible, and gives you one variable to adjust deliberately rather than a vague sense that today's pot came out different.
The five ounce cup
Drip coffee makers mark their carafes in 5 fluid ounce cups, a convention dating from mid-century American percolators. A measuring cup is 8 fluid ounces. So a machine's 12 cup capacity is 60 fl oz, not 96, and its own dosing suggestions are written for the smaller cup.
This is worth knowing because it cuts both ways. People who dose by measuring cups make coffee that is far too weak for the water, and people who follow the machine's scoop recommendation and then drink from a large mug are drinking roughly one and a half carafe cups at a time.
What this calculator assumes
Every estimate depends on figures that vary by supplier and conditions. These are the ones used here, so you can sanity-check the result against your own quote.
- Water is taken as 1 gram per millilitre, which is what allows a coffee-to-water ratio by weight to be worked out from a volume of water.
- Ratios are expressed as coffee to water by weight — 1:16 means 1 g of coffee for every 16 g of water. Some sources quote the inverse, so a figure like 6% refers to the same thing from the other direction.
- A level tablespoon of medium-ground coffee is taken as 5.3 g. This is the weakest figure on the page: grind size, roast level and how heaped the spoon is move it by 20% or more, which is exactly why weighing is better.
- The coffee maker cup is 5 fluid ounces, which is what the markings on a drip machine's carafe mean. It is not the 8 fluid ounce measuring cup, and this is the single most common reason a machine's own recommendations taste weak.
- Ratios apply to the water that reaches the coffee. A drip machine loses a little to the boiler and the grounds retain roughly twice their own weight, so the brewed volume in the cup is always less than the water you poured in.
- Espresso at around 1:2 is a different kind of measurement — a ratio of dry dose to liquid espresso out, not to water in. It is included for reference but pressure, grind and time matter more than the ratio alone.
Frequently asked questions
How much coffee per cup of water?
At a 1:16 ratio, about 15 g of coffee for a 240 ml measuring cup, or about 9 g for the 5 fl oz cup your coffee maker's carafe is marked in. That second figure catches people out — a machine's 10 cup line is 50 fl oz, not 80.
What is the golden ratio for coffee?
The Specialty Coffee Association's golden ratio is about 1:18, or 55 g of coffee per litre of water. Most people find something between 1:15 and 1:17 tastes better at home, and the range that is genuinely useful is 1:14 to 1:18. Below 1:12 you are brewing concentrate.
What ratio should I use for a French press?
Around 1:15, slightly stronger than pour-over. A French press does not filter out fines or oils, so the cup has more body at the same ratio, and the longer immersion extracts more. For a standard 1 litre press that is about 67 g of coffee.
Why does my coffee taste weak even at the right ratio?
Usually grind or temperature rather than dose. Too coarse a grind under-extracts however much coffee you use, and water below about 195 °F will taste thin and sour no matter the ratio. If the ratio is right and it still tastes weak, grind finer before adding more coffee.
Related calculators
Other cooking & kitchen jobs people price at the same time.
Cooking Measurement Converter
Convert cups, tablespoons, millilitres, grams and ounces for flour, sugar, butter and other common ingredients.
Recipe Scaling Calculator
Scale a recipe up or down by servings and convert each adjusted amount into cups, tablespoons, teaspoons, millilitres or grams.
Baking Pan Size Converter
Work out whether a recipe fits the pan you own, and how much to scale the batter when it does not.
Bread Hydration Calculator
Turn a baker's percentage formula into weights: water, salt and leaven for any quantity of flour, with sourdough starter accounted for.
Pizza Dough Calculator
Work backwards from how many pizzas you want and how big each ball should be to the exact flour, water, salt and yeast.
Yeast Conversion Calculator
Convert between instant yeast, active dry yeast and fresh yeast by weight, with teaspoon and packet equivalents.