Oven Temperature Converter
Gas mark 4, without the guesswork.
Oven Temperature Converter
Convert oven settings between Celsius, Fahrenheit, gas mark, and fan-assisted equivalents.
| Gas | °C | Chart °F | Fan °C |
|---|---|---|---|
| ¼ | 110 | 225 | 90 |
| ½ | 130 | 250 | 110 |
| 1 | 140 | 275 | 120 |
| 2 | 150 | 300 | 130 |
| 3 | 170 | 325 | 150 |
| 4 | 180 | 350 | 160 |
| 5 | 190 | 375 | 170 |
| 6 | 200 | 400 | 180 |
| 7 | 220 | 425 | 200 |
| 8 | 230 | 450 | 210 |
| 9 | 240 | 475 | 220 |
Conventional oven
180°C
356 °F · gas mark 4
- Celsius
- 180 °C
- Fahrenheit (exact)
- 356 °F
- Gas mark
- 4
- Fan-assisted
- 160 °C
Fan ovens are usually set about 20 °C lower than conventional. Oven thermostats vary, so trust a separate thermometer over the dial.
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What This Calculator Does
The Oven Temperature Converter translates a baking temperature between Celsius, Fahrenheit, UK gas marks, and the lower setting a fan-assisted oven usually needs. It shows the conventional figure first, then the fan equivalent, because a recipe written for a conventional oven will overbake in a fan oven set to the same number.
How It Works
Celsius and Fahrenheit are converted with the standard temperature formula. Gas marks use the conventional chart printed in British recipe books, where each mark corresponds to a rounded Celsius and Fahrenheit pair rather than a strict mathematical conversion. The result panel shows the exact Fahrenheit value, so it can differ by a few degrees from the rounded chart. The fan setting is estimated as 20 °C below the conventional temperature, the usual manufacturer guidance.
Example
Gas mark 4 is conventionally 180 °C or 350 °F, and about 160 °C in a fan oven. The exact conversion of 180 °C is 356 °F, which is why the result panel can differ by a few degrees from the rounded chart. A recipe that says “180 °C fan” therefore wants a conventional oven at 200 °C, which is gas mark 6.
Formula
°F = °C × 9/5 + 32°C = (°F − 32) × 5/9fan °C ≈ conventional °C − 20Gas 1 = 140 °C, gas 4 = 180 °C, gas 9 = 240 °CThe chart is conventional, not a continuous formula; use the nearest mark for values between.
Reading the Results
Celsius
The conventional oven temperature. Most European and Australian recipes are written in Celsius, and fan ovens usually need 20 °C less.
Gas mark
The nearest UK gas setting. Gas marks are coarse steps, so a recipe at 175 °C is usually cooked at gas mark 4 (180 °C) or 3 (170 °C) depending on the baker.
Sources and References
NIST Special Publication 811 — Guide for the Use of the SI
Celsius and Fahrenheit conversion
The authoritative temperature conversion used here.
King Arthur Baking — Oven Temperature Conversion
Conventional and convection oven equivalents
Explains why convection ovens are set lower and by how much.
Food Standards Agency — Cooking safely
Oven and food safety guidance
Reminds cooks that oven thermostats drift and a separate thermometer is more reliable than the dial.
References identify the method or data behind this calculator. Where a standard or tariff changes, the current edition applies, and the assumptions stated above take precedence over a remembered figure.
Frequently Asked Questions
Is a fan oven hotter than a conventional oven?
Yes, effectively. A fan moves hot air around the cavity, so heat transfers faster and the food cooks sooner at the same dial setting. Manufacturers usually advise setting a fan oven about 20 °C lower than a conventional one.
Why is gas mark 4 not exactly 180 °C?
Gas marks are a coarse scale inherited from early gas ovens, and each mark maps to a rounded pair of Celsius and Fahrenheit values. Gas mark 4 is defined as about 180 °C / 350 °F, but real ovens vary by 10–20 °C either way.
Should I trust the oven dial?
Not for anything delicate. Domestic oven thermostats commonly drift, and the displayed temperature is not the same as the average cavity temperature. An inexpensive oven thermometer will tell you what the oven is actually doing.
What about air fryers and convection microwaves?
They are fan ovens with a smaller cavity, so they run hotter and faster still. Start about 20 °C below the fan setting and check early; the conversion here is for a full-size fan oven.