Use the Oven Temperatures Explained Celsius Fahrenheit Fan and Gas Mark
In the UK, oven temperatures are commonly shown as conventional Celsius, fan oven Celsius, Fahrenheit or gas mark. A common everyday example is that 180°C conventional is roughly 160°C fan, 350°F or gas mark 4.
Fan ovens usually need a lower temperature than conventional ovens because the fan circulates heat more efficiently. A common estimate is to reduce a conventional Celsius temperature by about 20°C for fan cooking. Related Calculatorz pages include fan oven.
Need a quick conversion?
Use the oven temperature converter to switch between Celsius, Fahrenheit, fan oven and UK gas mark settings.
The four common oven temperature systems
Oven settings can look confusing because different recipes use different systems. UK recipes often use Celsius and gas mark, while older or international recipes may use Fahrenheit.
Common oven temperature conversions
The table below gives practical kitchen equivalents. They are useful for everyday cooking, but actual oven performance can vary by model, shelf position and whether the oven is preheated properly.
| Conventional oven | Fan oven approx. | Fahrenheit approx. | Gas mark approx. | Typical use |
|---|---|---|---|---|
| 120°C | 100°C fan | 250°F | Gas mark ½ | Very low / slow drying |
| 140°C | 120°C fan | 275°F | Gas mark 1 | Low and slow cooking |
| 160°C | 140°C fan | 325°F | Gas mark 3 | Gentle baking |
| 180°C | 160°C fan | 350°F | Gas mark 4 | Cakes, bakes and everyday roasting |
| 190°C | 170°C fan | 375°F | Gas mark 5 | Pastry, pies and roasting |
| 200°C | 180°C fan | 400°F | Gas mark 6 | Roasting vegetables, tray bakes |
| 220°C | 200°C fan | 425°F | Gas mark 7 | Hot roasting and crisping |
| 240°C | 220°C fan | 475°F | Gas mark 9 | Very hot cooking, pizza-style heat |
How Celsius and Fahrenheit convert
Celsius and Fahrenheit are both temperature scales. You can convert between them with a formula, then round to a practical oven setting.
Fahrenheit = (Celsius × 9 ÷ 5) + 32
Celsius = (Fahrenheit - 32) × 5 ÷ 9
Example:
180°C × 9 ÷ 5 + 32 = 356°F
In kitchen terms, this is usually rounded to 350°F.This is why some tables show slightly different values. A precise maths conversion and a practical recipe conversion are not always the same thing.
How fan oven temperatures work
A fan oven circulates hot air around the oven cavity, so food often cooks more evenly and efficiently. That is why fan oven temperatures are commonly set lower than conventional oven temperatures.
Common fan oven estimate:
Fan temperature = conventional Celsius - 20°C
Example:
180°C conventional ≈ 160°C fanThis is a rule of thumb, not a law. Some ovens run hot or cold, and some recipes already state a fan temperature separately.
What gas mark means
Gas mark is a numbered oven setting used for gas ovens. Instead of choosing 180°C or 350°F, a recipe may say gas mark 4.
Gas mark conversions are normally taken from practical lookup tables rather than a simple one-line formula. That is why it is best to use a converter or table when switching between gas mark and electric oven temperatures.
When you may need to adjust the temperature
Oven conversions give you a starting point. You may still need to adjust temperature or cooking time based on the recipe, equipment and food size.
- Use the recipe’s fan setting if it gives one, rather than converting manually.
- Reduce heat slightly if food browns too quickly before the middle is cooked.
- Increase time rather than temperature for larger or deeper dishes.
- Preheat the oven unless the recipe says otherwise.
- For baking, avoid opening the oven door too often because heat drops quickly.
Oven temperature when scaling a recipe
When you scale a recipe, the ingredient amounts may change, but the oven temperature often stays the same. What usually changes is the pan size, depth of mixture and cooking time.
For example, doubling a tray bake does not automatically mean doubling the temperature. A deeper mixture may need longer at the same temperature, while a larger shallow tray may cook closer to the original timing.
Common oven conversion mistakes
- Using a conventional Celsius temperature in a fan oven without reducing it.
- Treating Fahrenheit conversions as exact recipe settings instead of rounded kitchen settings.
- Assuming every gas mark table is perfectly exact.
- Forgetting to preheat the oven before timing the recipe.
- Changing temperature when the better fix is changing cooking time or pan size.
FAQs
What is 180°C in a fan oven?
A common estimate is 160°C fan. Fan ovens move hot air around the oven, so they often need a lower setting than conventional ovens.
What gas mark is 180°C?
180°C conventional is commonly treated as gas mark 4. It is also roughly 350°F or 160°C fan.
What is 200°C in gas mark?
200°C conventional is commonly treated as gas mark 6. A fan oven equivalent is often about 180°C fan.
Is 350°F the same as 180°C?
350°F is approximately 177°C, so recipes often round it to 180°C conventional or 160°C fan.
Should I reduce temperature for a fan oven?
Usually, yes. A common rule of thumb is to reduce a conventional Celsius temperature by about 20°C, unless the recipe already gives a fan oven setting.
Are oven temperature conversions exact?
No. Formulas can convert Celsius and Fahrenheit exactly, but practical cooking settings are rounded. Ovens also vary by model, age and calibration.
Sources and notes
This guide uses common UK kitchen conversion conventions for Celsius, Fahrenheit, fan oven and gas mark settings. Oven performance varies, so treat conversions as practical starting points rather than exact guarantees.