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Coffee Ratio Calculator

Computes the grams of ground coffee for a given amount of water (or the water for a given dose) from a brew ratio, using method-specific default ratios (drip and pour-over 1:16, French press 1:15, AeroPress 1:13, cold brew concentrate 1:8, espresso 1:2) or a custom ratio.

When to use

You want to know how much coffee to use for a certain volume of water, how much water a dose of coffee needs, or the ratio implied by amounts you already used.

Do not use when: You need caffeine content or extraction/TDS calculations; ratios here are by weight of dry coffee and water only.

Formula

coffee_g = water_ml / ratio (or water_ml = coffee_g × ratio); coffee_g_per_liter = 1000 / ratio; tablespoons ≈ coffee_g / 5.5

Ratios are by weight; 1 ml of water weighs 1 g. The SCA Golden Cup Standard (55 g/L ± 10 %) corresponds to about 1:16.5–1:20; espresso ratios describe beverage yield rather than water added.

Inputs

Parameter	Type	Unit	Required	Description
`water_ml`	number	ml	no	Brew water in millilitres (≈ grams). Give this and/or coffee_g. Range: > 0, ≤ 100000
`coffee_g`	number	g	no	Ground coffee in grams. If both water_ml and coffee_g are given, the calculator reports the ratio they imply. Range: > 0, ≤ 10000
`brew_method`	enum: drip \| pour_over \| french_press \| aeropress \| cold_brew \| espresso		default drip	Sets the default ratio (water parts per 1 part coffee) when no custom ratio is given.
`ratio`	number		no	Water parts per 1 part coffee by weight, e.g. 16 for 1:16; overrides the brew-method default. Range: ≥ 1, ≤ 30

Outputs

Output	Type	Unit	Description
`coffee_g`	number	g	Ground coffee dose.
`water_ml`	number	ml	Brew water (for espresso: beverage weight in grams).
`ratio`	number		Water parts per 1 part coffee.
`ratio_text`	string		Ratio written as 1:N.
`coffee_g_per_liter`	number	g/L	Grams of coffee per litre of water; the SCA Golden Cup range for filter coffee is 55 g/L ± 10 % (49.5–60.5 g/L).
`tablespoons_approx`	number	tbsp	Approximate volume of the dose at ~5.5 g of medium-ground coffee per level tablespoon; a scale is more accurate.

Example

500 ml drip coffee: {"water_ml":500,"brew_method":"drip"} → {"coffee_g":31.3,"water_ml":500,"ratio":16,"ratio_text":"1:16","coffee_g_per_liter":62.5}

18 g espresso dose: {"coffee_g":18,"brew_method":"espresso"} → {"water_ml":36,"coffee_g":18,"ratio":2,"ratio_text":"1:2"}

GET https://tttkmbb.com/api/v1/calculate/coffee-ratio?water_ml=500&brew_method=drip

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/coffee-ratio (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/coffee-ratio · Markdown: https://tttkmbb.com/food/coffee-ratio.md · JSON definition: https://tttkmbb.com/food/coffee-ratio.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="coffee-ratio"
OpenAPI operationId: calculate_coffee_ratio
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

Specialty Coffee Association – Brewing best practices and Golden Cup Standard (55 g/L ± 10 %) (standard)

FAQ

Should I measure water in ml or grams?

They are interchangeable for brewing (1 ml = 1 g). Weighing both coffee and water on a scale is the most repeatable method.

Why does cold brew use 1:8?

That is a concentrate ratio; dilute the finished brew roughly 1:1 with water or milk. For ready-to-drink cold brew use about 1:15.

Related calculators

Cooking Measurement Converter — Convert cups or fluid ounces of water to millilitres first.