# 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.

- Calculator id: `coffee-ratio` · Category: Food & Cooking (`food`) · Tool name: `calculate_coffee_ratio`
- Canonical page: https://tttkmbb.com/food/coffee-ratio · This document: https://tttkmbb.com/food/coffee-ratio.md · JSON definition: https://tttkmbb.com/food/coffee-ratio.json

## Purpose

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.

**Use when:** 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.

## Input

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

## Output

| Field | 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. |

## 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.

## Data Sources

- Specialty Coffee Association – Brewing best practices and Golden Cup Standard (55 g/L ± 10 %) — https://sca.coffee/research/protocols-best-practices (standard, retrieved 2026-09-23)

Data freshness: `static`. Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output.

## API

- `GET https://tttkmbb.com/api/v1/calculate/coffee-ratio?`
- `POST https://tttkmbb.com/api/v1/calculate/coffee-ratio` with JSON body `{"inputs": {…}}`
- Response: unified envelope (`success`, `request`, `result.values`, `result.units`, `sources`, `freshness`, `timestamp`, `next_actions`, `links`); see https://tttkmbb.com/docs/response-format.md
- Schema: https://tttkmbb.com/api/v1/calculators/coffee-ratio · OpenAPI operationId `calculate_coffee_ratio` in https://tttkmbb.com/openapi.json
- Authentication: none. Rate limit: fair use, see https://tttkmbb.com/docs/rate-limits.md.

## MCP

- Server: `https://tttkmbb.com/mcp` (Streamable HTTP, JSON-RPC 2.0, no auth)
- Tool:  `run_calculator` with `{"calculator_id": "coffee-ratio", "inputs": {…}}`

## Example

- 500 ml drip coffee: inputs `{"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: inputs `{"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
```

## Limitations

You need caffeine content or extraction/TDS calculations; ratios here are by weight of dry coffee and water only. 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. All values are computed from the formula above; no measurement or live data is involved.

## 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

- [Cooking Measurement Converter](https://tttkmbb.com/food/cooking-converter.md) — Convert cups or fluid ounces of water to millilitres first.