How much water do I need for 30 g of coffee?

At 1:16, 30 g of coffee needs 480 g of water, making 510 g of coffee plus water going into the brewer. For the same coffee weight, changing the ratio to 1:15 gives 450 g of water, and 1:17 gives 510 g. The third worked example under the calculator compares those two ratios.

Can I calculate a French press coffee to water ratio?

Yes. Enter the coffee-to-water mass ratio from your French press recipe in Ratio, then enter either the dry coffee weight or the water weight. The calculator solves the other weight and scales the batch across servings. For example, if your recipe specifies 1:12, 30 g of coffee needs 360 g of water. This is recipe arithmetic; the page does not choose a ratio or predict taste.

Can I use it for drip, filter or pour-over coffee?

Yes. The same mass calculation works for a drip or filter recipe, including pour-over recipes using a Chemex or V60. Enter your recipe's ratio and a coffee or water weight. These are independent calculations, with no manufacturer recipe, affiliation, brew-time setting or temperature recommendation.

Can I scale a cold brew coffee recipe?

Yes, when the ratio describes dry coffee to water going into the brew by weight. Enter that ratio and either weight, then use One serving to multiply a recipe or The whole batch to divide it across servings. The calculator does not predict concentrate yield or calculate how much water or milk to add after brewing.

Can I calculate a coffee golden ratio?

If your recipe calls its coffee-to-water mass ratio a golden ratio, enter that ratio in Ratio. The page opens at 1:16 as an example and can calculate other ratios; it does not identify one ratio as best or measure extraction or taste. This is coffee recipe scaling, not a geometric golden-ratio calculation.

How much coffee do I need for a litre of water?

This calculator takes weighed water in grams and does not convert litres into grams. For a 1:12 recipe with 1,000 g of water, it calculates 83.3 g of coffee. Split that batch across 4 servings and it shows 20.8 g of coffee and 250 g of water per serving.

Can I use tablespoons or scoops instead of a scale?

The calculator does not convert coffee volumes to weights because a spoonful's weight depends on the grind and the beans. Enter numeric gram weights, such as 30. A typed or pasted mass may also use g, kg or mg; kilograms and milligrams are converted into grams. Tablespoons, cups and fluid ounces are refused.

Is the water figure what ends up in my cup?

The water figure is water going into the brewer. Brew output is measured separately. Enter the weight of the whole batch in Brewed out: with 480 g of water in and 415 g of brew out, the displayed difference is 65 g and the coffee-to-brew-out ratio is 1 : 13.83. The difference compares two scale readings; it does not measure extraction or predict yield.

Does it calculate an espresso target yield?

No. The Ratio field describes coffee to input water, not coffee dose to liquid espresso output. Entering 18 g at 1:2 calculates 36 g of input water; it is not a target shot weight. Brewed out can compare an output you actually weighed with known inputs, but this page has no mode for calculating a target espresso yield.

How do I scale a recipe up for more cups?

Leave Weights are on The whole batch to divide fixed weights across servings: 30 g of coffee and 480 g of water across 2 servings is 15 g of coffee and 240 g of water each. Switch to One serving to multiply: 20 g of coffee at 1:16 needs 320 g of water for one serving, and 2 servings gives a batch of 40 g of coffee and 640 g of water.

Can it work backwards from a water weight?

Yes. Enter a weight in Water to calculate Coffee: 1,000 g of water at 1:16 needs 62.5 g of coffee. The field you edit last is the known weight. Ratio is always written coffee first, water second, even when you solve for coffee. For a water-to-coffee ratio of 16:1, enter 1:16 in Ratio.

Does it round the weights?

Weights display to a tenth of a gram and worked output ratios to a hundredth, with a note when figures are rounded. The calculation keeps exact fractions: 18.3 g of coffee at 1:16.5 gives exactly 301.95 g of water and displays 302 g; rounding the nearest floating-point product instead gives 301.9. A nonzero weight that would round to zero at a tenth displays up to three decimal places, but values below that precision can still display as zero.

Why has the calculator refused my entry?

Use a positive weight with up to three decimals and a positive ratio with up to two decimals on each side. Write a ratio as 1:15, 1 / 15, 1 to 15 or just 15; spaces inside a number are refused. Servings must be whole, from 1 to 1,000. Each coffee, water or measured brew weight is limited to 1,000,000 g, including scaled coffee and water totals. Volumes, unsupported units and measured brew heavier than the coffee plus water input are refused. If a scale reading looks inconsistent, check that the empty container was tared.

Is my recipe saved or sent anywhere?

Recipe entries are saved in this browser's local storage and are not uploaded by the calculator. If storage is blocked or full, calculations still work but settings are not remembered. Copy puts the recipe and its calculation on the clipboard when the browser permits it; there is no recipe file download or PDF export.

Coffee Ratio Calculator

Scale coffee grounds and water by weight for the ratio in your recipe. Enter either weight to calculate the other, then split a whole batch across servings or multiply one serving into a batch. Water means the amount going into the brewer; measured brew output is optional.

1 : 1630 g coffee2 servingsGrams

ratio           1 : 16   by mass
coffee            30 g
water            480 g   30 x 16

per serving       15 g   coffee
                 240 g   water
total in         510 g   coffee plus water

yield is not measured, only what goes in

Ratio

Coffee

Water

Servings

Weights are

Brewed out, if you weighed it

The weights are the whole brew, and a serving is the batch divided by the number of servings.

1 : 16 by mass: 30 g of coffee to 480 g of water, 2 servings of 15 g of coffee and 240 g of water.

The water figure is what goes into the brewer, not what comes out of it: wet grounds keep some of it back. Weigh the brew and enter it under Brewed out to see how much stayed behind.

Three brews, worked

Compare solving for water, solving for coffee, and changing the ratio while keeping the coffee weight fixed.

1:16, 20 g coffeesolve water
320 g
1:16, 1,000 g watersolve coffee
62.5 g
30 g at 1:15 and at 1:17same coffee
450 g and 510 g

Accuracy. Exact arithmetic by mass: water is coffee times the ratio you picked, and both scale with servings. Everything is weighed in grams because a scoop or a tablespoon of coffee changes with the grind and the bean, so no volume conversion is assumed. It scales what goes in and claims nothing about extraction, strength or taste.

Common questions

How much water do I need for 30 g of coffee?: At 1:16, 30 g of coffee needs 480 g of water, making 510 g of coffee plus water going into the brewer. For the same coffee weight, changing the ratio to 1:15 gives 450 g of water, and 1:17 gives 510 g. The third worked example under the calculator compares those two ratios.
Can I calculate a French press coffee to water ratio?: Yes. Enter the coffee-to-water mass ratio from your French press recipe in Ratio, then enter either the dry coffee weight or the water weight. The calculator solves the other weight and scales the batch across servings. For example, if your recipe specifies 1:12, 30 g of coffee needs 360 g of water. This is recipe arithmetic; the page does not choose a ratio or predict taste.
Can I use it for drip, filter or pour-over coffee?: Yes. The same mass calculation works for a drip or filter recipe, including pour-over recipes using a Chemex or V60. Enter your recipe's ratio and a coffee or water weight. These are independent calculations, with no manufacturer recipe, affiliation, brew-time setting or temperature recommendation.
Can I scale a cold brew coffee recipe?: Yes, when the ratio describes dry coffee to water going into the brew by weight. Enter that ratio and either weight, then use One serving to multiply a recipe or The whole batch to divide it across servings. The calculator does not predict concentrate yield or calculate how much water or milk to add after brewing.
Can I calculate a coffee golden ratio?: If your recipe calls its coffee-to-water mass ratio a golden ratio, enter that ratio in Ratio. The page opens at 1:16 as an example and can calculate other ratios; it does not identify one ratio as best or measure extraction or taste. This is coffee recipe scaling, not a geometric golden-ratio calculation.
How much coffee do I need for a litre of water?: This calculator takes weighed water in grams and does not convert litres into grams. For a 1:12 recipe with 1,000 g of water, it calculates 83.3 g of coffee. Split that batch across 4 servings and it shows 20.8 g of coffee and 250 g of water per serving.
Can I use tablespoons or scoops instead of a scale?: The calculator does not convert coffee volumes to weights because a spoonful's weight depends on the grind and the beans. Enter numeric gram weights, such as 30. A typed or pasted mass may also use g, kg or mg; kilograms and milligrams are converted into grams. Tablespoons, cups and fluid ounces are refused.
Is the water figure what ends up in my cup?: The water figure is water going into the brewer. Brew output is measured separately. Enter the weight of the whole batch in Brewed out: with 480 g of water in and 415 g of brew out, the displayed difference is 65 g and the coffee-to-brew-out ratio is 1 : 13.83. The difference compares two scale readings; it does not measure extraction or predict yield.
Does it calculate an espresso target yield?: No. The Ratio field describes coffee to input water, not coffee dose to liquid espresso output. Entering 18 g at 1:2 calculates 36 g of input water; it is not a target shot weight. Brewed out can compare an output you actually weighed with known inputs, but this page has no mode for calculating a target espresso yield.
How do I scale a recipe up for more cups?: Leave Weights are on The whole batch to divide fixed weights across servings: 30 g of coffee and 480 g of water across 2 servings is 15 g of coffee and 240 g of water each. Switch to One serving to multiply: 20 g of coffee at 1:16 needs 320 g of water for one serving, and 2 servings gives a batch of 40 g of coffee and 640 g of water.
Can it work backwards from a water weight?: Yes. Enter a weight in Water to calculate Coffee: 1,000 g of water at 1:16 needs 62.5 g of coffee. The field you edit last is the known weight. Ratio is always written coffee first, water second, even when you solve for coffee. For a water-to-coffee ratio of 16:1, enter 1:16 in Ratio.
Does it round the weights?: Weights display to a tenth of a gram and worked output ratios to a hundredth, with a note when figures are rounded. The calculation keeps exact fractions: 18.3 g of coffee at 1:16.5 gives exactly 301.95 g of water and displays 302 g; rounding the nearest floating-point product instead gives 301.9. A nonzero weight that would round to zero at a tenth displays up to three decimal places, but values below that precision can still display as zero.
Why has the calculator refused my entry?: Use a positive weight with up to three decimals and a positive ratio with up to two decimals on each side. Write a ratio as 1:15, 1 / 15, 1 to 15 or just 15; spaces inside a number are refused. Servings must be whole, from 1 to 1,000. Each coffee, water or measured brew weight is limited to 1,000,000 g, including scaled coffee and water totals. Volumes, unsupported units and measured brew heavier than the coffee plus water input are refused. If a scale reading looks inconsistent, check that the empty container was tared.
Is my recipe saved or sent anywhere?: Recipe entries are saved in this browser's local storage and are not uploaded by the calculator. If storage is blocked or full, calculations still work but settings are not remembered. Copy puts the recipe and its calculation on the clipboard when the browser permits it; there is no recipe file download or PDF export.

Exact arithmetic by mass: water is coffee times the ratio you picked, and both scale with servings. Everything is weighed in grams because a scoop or a tablespoon of coffee changes with the grind and the bean, so no volume conversion is assumed. It scales what goes in and claims nothing about extraction, strength or taste.