Oven Temperature Conversion: °F, °C, and Gas Mark 🌎

How oven temperature conversion works

Oven temperatures are expressed in three scales worldwide: Fahrenheit (°F) used in the US and some older Canadian recipes, Celsius (°C) standard in Europe, Australia, and most of the world, and Gas Mark used in older British and Irish recipes. This calculator converts between all three simultaneously using exact thermometric formulas.

How it is calculated

All conversions pass through Celsius as the intermediate step:

// Fahrenheit → Celsius
°C = (°F − 32) × 5 / 9

// Celsius → Fahrenheit
°F = °C × 9 / 5 + 32

// Celsius → Gas Mark  (valid range: Gas Mark ¼ to 10)
Gas Mark = (°C − 121) / 14

// Gas Mark → Celsius
°C = Gas Mark × 14 + 121

The Gas Mark formula is the standard linear approximation used by the British Standards Institution. It matches the official Gas Mark reference table within ±3°C across the full domestic cooking range.

Convection adjustment: fan ovens circulate air and transfer heat more efficiently, so for any recipe written for a conventional oven you subtract 25°F (14°C) from the target temperature. The calculator applies this to give you a suggested convection set-point.

Worked example: converting Gas Mark 6

Your British recipe calls for Gas Mark 6. You have a conventional US oven.

1. Gas Mark → °C: 6 × 14 + 121 = 205°C
2. °C → °F: 205 × 9/5 + 32 = 401°F
3. Gas Mark output: Gas Mark 6
4. Heat description: Moderately Hot (between 375°F and 400°F band)
5. If using a convection oven: reduce to 401 − 25 = 376°F (or 205 − 14 = 191°C)

So set your conventional oven to about 400°F (205°C), or your fan oven to about 375°F (190°C).

Oven temperature reference table

The most useful values for everyday baking and roasting — use this to find your setting at a glance:

> Recipe rounding note: Many recipes round °C to the nearest 5 or 10 (e.g., 177°C → 180°C). This is a convention, not an error — domestic ovens are rarely accurate to within 5°C.

Convection vs conventional oven

Convection ovens (also called fan ovens or fan-forced ovens) use an internal fan to circulate hot air around food. This makes heat transfer more uniform and roughly 20–25% faster than a conventional oven. The industry-standard adjustment is −25°F / −14°C from the recipe temperature. Alternatively, you can keep the same temperature and reduce baking time by about 20–25%, checking for doneness a few minutes early.

Accuracy limits