# Oven Temperature Converter

> Converts an oven setting between degrees Celsius, degrees Fahrenheit and British gas marks, reports the descriptive term (slow, moderate, hot) and the equivalent fan (convection) oven setting, which is 20 °C lower.

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

## Purpose

Converts an oven setting between degrees Celsius, degrees Fahrenheit and British gas marks, reports the descriptive term (slow, moderate, hot) and the equivalent fan (convection) oven setting, which is 20 °C lower.

**Use when:** A recipe gives an oven temperature in a scale your oven does not use, mentions a gas mark, or you need the fan-oven equivalent of a conventional temperature.

**Do not use when:** You need a general temperature conversion that is not an oven setting (use temperature), or internal food doneness temperatures (use turkey-cooking-time for poultry).

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `temperature` | number |  | required | Oven temperature in temperature_unit, or the gas mark number (0.25, 0.5, 1 … 10). (min 0, max 600) |
| `temperature_unit` | enum: c \| f \| gas_mark |  | optional, default "c" | Scale of the input value. |
| `input_is_fan_oven` | boolean |  | optional, default false | true if the given temperature is already a fan/convection setting; it is then raised by 20 °C to the conventional equivalent before conversion. |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `celsius` | number | °C | Conventional (static) oven temperature in Celsius. |
| `fahrenheit` | number | °F | Conventional oven temperature in Fahrenheit. |
| `gas_mark` | string |  | Nearest British gas mark (¼, ½, 1–10). |
| `gas_mark_exact` | number |  | Unrounded gas mark position, (°F − 250) / 25 for gas mark 1 and above. |
| `fan_oven_c` | number | °C | Conventional temperature minus 20 °C. |
| `fan_oven_f` | number | °F | Conventional Fahrenheit temperature minus 25 °F (US convection rule). |
| `description` | string |  | Traditional term for this heat: very slow, slow, moderately slow, moderate, moderately hot, hot, very hot. |
| `conversion_table` | list |  | Gas marks ¼–10 with °F, °C and fan °C. |

## Formula

`°F = °C × 9/5 + 32; gas mark n ≥ 1: °F = 250 + 25·n (gas mark 1 = 275 °F, +25 °F per mark); gas mark ½ = 250 °F, ¼ = 225 °F; fan °C = conventional °C − 20; fan °F = conventional °F − 25`

Gas mark values follow the British scale defined in 25 °F steps from 275 °F. The 20 °C (25 °F) fan-oven reduction is the usual manufacturer guidance; recipes often round Celsius values (e.g. gas mark 6 = 400 °F = 204 °C is printed as 200 °C).

## Data Sources

- Wikipedia – Gas mark — https://en.wikipedia.org/wiki/Gas_mark (reference, retrieved 2026-09-24)
- Wikipedia – Oven temperatures (descriptive terms and fan-oven adjustment) — https://en.wikipedia.org/wiki/Oven_temperatures (reference, retrieved 2026-09-24)

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/oven-temperature?temperature=…`
- `POST https://tttkmbb.com/api/v1/calculate/oven-temperature` 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/oven-temperature · OpenAPI operationId `convert_oven_temperature` 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": "oven-temperature", "inputs": {…}}`

## Example

- 180 °C: inputs `{"temperature":180,"temperature_unit":"c"}` → `{"celsius":180,"fahrenheit":356,"gas_mark":"4","gas_mark_exact":4.24,"fan_oven_c":160,"fan_oven_f":331,"description":"Moderate"}`
- Gas mark 6: inputs `{"temperature":6,"temperature_unit":"gas_mark"}` → `{"fahrenheit":400,"celsius":204,"gas_mark":"6","fan_oven_c":184,"description":"Moderately hot"}`

```
GET https://tttkmbb.com/api/v1/calculate/oven-temperature?temperature=180&temperature_unit=c
```

## Limitations

You need a general temperature conversion that is not an oven setting (use temperature), or internal food doneness temperatures (use turkey-cooking-time for poultry). Gas mark values follow the British scale defined in 25 °F steps from 275 °F. The 20 °C (25 °F) fan-oven reduction is the usual manufacturer guidance; recipes often round Celsius values (e.g. gas mark 6 = 400 °F = 204 °C is printed as 200 °C). All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**Why does my recipe say gas mark 4 = 180 °C when the table gives 177 °C?**

Gas mark 4 is defined as 350 °F = 176.7 °C; recipe writers round to the nearest 10 °C. Ovens are rarely accurate to better than ±10 °C anyway.

**Should I always reduce the temperature for a fan oven?**

Yes, by about 20 °C (25 °F) unless the recipe already states a fan setting; the moving air transfers heat faster. Some recipes also shorten the time by roughly 10 %.

**How do I enter gas mark ½ or ¼?**

As 0.5 or 0.25 with temperature_unit=gas_mark.

## Related

- [Temperature Converter](https://tttkmbb.com/conversion/temperature.md) — General temperature conversion including kelvin.
- [Cake Pan Conversion Calculator](https://tttkmbb.com/food/cake-pan-conversion.md) — Adjust recipes for a different pan size.
- [Turkey Cooking Time Calculator](https://tttkmbb.com/food/turkey-cooking-time.md) — Roasting times at a given oven temperature.