Why Oven Temperature Confusion Happens
Oven temperature is one of the most common sources of baking failure – not because the recipe is wrong, but because three different systems are in use simultaneously around the world:
- Fahrenheit (°F) – standard in the United States
- Celsius (°C) – standard in most of the rest of the world
- Gas Marks – still used in some British and Irish recipes
Add fan (convection) ovens with different behaviour to conventional ovens, and a simple recipe step becomes genuinely confusing.
Fahrenheit to Celsius Conversion
The formula: °C = (°F − 32) × 5/9
The reverse: °F = (°C × 9/5) + 32
For oven temperatures specifically, these approximate conversions are good enough:
| °F | °C (approx.) |
|---|---|
| 250°F | 120°C |
| 275°F | 135°C |
| 300°F | 150°C |
| 325°F | 165°C |
| 350°F | 175°C |
| 375°F | 190°C |
| 400°F | 200°C |
| 425°F | 220°C |
| 450°F | 230°C |
| 475°F | 245°C |
| 500°F | 260°C |
Gas Mark Reference Table
Gas marks are used in some British, Irish, and Australian recipes. They are unitless numbers corresponding to specific temperatures:
| Gas Mark | °C | °F | Description |
|---|---|---|---|
| ¼ | 110 | 225 | Very low / keep-warm |
| ½ | 130 | 250 | Very low |
| 1 | 140 | 275 | Very low |
| 2 | 150 | 300 | Low |
| 3 | 170 | 325 | Moderate-low |
| 4 | 180 | 350 | Moderate (most baked goods) |
| 5 | 190 | 375 | Moderate-high |
| 6 | 200 | 400 | Hot |
| 7 | 220 | 425 | Very hot |
| 8 | 230 | 450 | Very hot |
| 9 | 240 | 475 | Extremely hot |
Fan (Convection) Ovens
Fan ovens (called convection ovens in the US and fan-assisted in the UK) circulate hot air with a fan, cooking food more evenly and efficiently than conventional (static) ovens.
The rule: Fan ovens cook about 10–20°C (or 25°F) hotter than conventional ovens at the same setting. To adapt:
- Conventional recipe → fan oven: Reduce temperature by 15–20°C (25°F) or reduce cooking time by 10–15%
- Fan recipe → conventional oven: Increase temperature by 15–20°C or increase cooking time by 10–15%
When to use fan setting:
- Roasting meat and vegetables (faster browning, even cooking)
- Multiple trays at the same time (fan distributes heat more evenly)
- Cookies and biscuits (even browning)
When to avoid fan setting:
- Delicate baked goods (soufflés, cheesecakes, custards) – the air movement can cause uneven rising
- Bread in the first phase of baking – steam retention matters more than air circulation initially
Common Baking Temperatures for Reference
| Food | Conventional °C | Fan °C | Notes |
|---|---|---|---|
| Sponge cake | 180°C | 160°C | Until skewer comes out clean |
| Cookies | 190°C | 170°C | Watch for colour |
| Roast chicken | 200°C | 180°C | Until 74°C internal |
| Bread | 220°C | 200°C | + steam in first 10 min |
| Pastry (blind bake) | 200°C | 180°C | |
| Cheesecake | 170°C | 150°C | Slow, gentle heat |
| Pizza | 240°C+ | 220°C+ | Max heat, preheated stone/tray |
Calibrating Your Oven
Consumer ovens are often inaccurate – off by 10–25°C from the dial setting. If your baked goods are consistently under or over-done at the stated temperature, invest in an oven thermometer (a few euros/dollars at any kitchen shop). Place it in the centre of the oven, heat to your usual temperature, and check the actual reading.
Converting Quickly
The Oven Temperature Converter on this site converts between Fahrenheit, Celsius, and Gas Marks in both directions and includes a fan adjustment option, instantly.
Summary
350°F = 175°C = Gas Mark 4 is the most useful conversion to memorize. Fan ovens run hot – reduce by 15–20°C compared to conventional recipes. Gas marks are a British system with a simple table lookup. An oven thermometer is the fastest fix for consistent baking failures.