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Oven Temperature Converter
Converts between oven temperature scales and gives both answers: the exact arithmetic and the conventional setting your dial actually has. Shows how far apart they are, handles fractional gas marks, and applies the fan oven adjustment.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
The setting to use
The exact arithmetic
The full oven table
| Gas | °F | °C | Fan °C | Description |
|---|
The °C column is the conventional recipe figure, not the exact conversion — see the note above about why they differ.
Converted in this page; nothing is uploaded. Worth keeping in perspective: domestic oven thermostats are commonly out by considerably more than the few degrees these rounding conventions differ by, so an oven thermometer will tell you more than any converter can. Use the practical setting and trust the food.
How to use it
- Type the temperature your recipe gives and say which scale it is in.
- Use the top row — that is the setting your oven actually has.
- Tick the fan box if your oven is fan-assisted.
- Ignore the exact figure unless you are curious why the two differ.
The familiar table is not a conversion table
This is the thing worth knowing, and almost no converter mentions it. Everyone treats 350°F and 180°C as the same oven setting. They are not the same temperature:
350 °F exactly = 176.67 °C
180 °C exactly = 356.00 °F
the gap 6 °F, or 3.3 °C
Both are round numbers on their own scale, which is the entire reason they are paired. The cookbook table is a list of tidy dial settings that sit near each other, not the output of a formula — and once you know that, the mismatch stops being confusing.
And the error is not consistent
You might hope to learn a single correction and apply it. There is not one. The discrepancy between the exact conversion and the conventional pairing swings in both directions and by very different amounts:
325 °F ↔ 170 °C exact 162.8 convention is 7.2 °C higher
350 °F ↔ 180 °C exact 176.7 3.3 °C higher
375 °F ↔ 190 °C exact 190.6 0.6 °C lower — almost exact
400 °F ↔ 200 °C exact 204.4 4.4 °C lower
500 °F ↔ 250 °C exact 260.0 10.0 °C lower
So a recipe converted at the top of the range is being asked to run a full ten degrees cooler than the arithmetic suggests, while one at 375°F is essentially unaffected. This tool tells you the size of the gap for whatever you enter rather than leaving you to wonder.
How gas marks are defined
The gas scale is genuinely a formula, unlike the Celsius column. Gas mark 1 is 275°F, and each mark up adds 25°F — so gas mark N is 250 + 25N degrees Fahrenheit. That reproduces the standard table exactly, with gas 4 at 350°F, gas 6 at 400°F and gas 8 at 450°F.
Below gas 1 the scale goes fractional rather than to zero: gas ½ at 250°F and gas ¼ at 225°F, for slow-cooking, drying and meringues. Because the marks are 25°F apart, a gas oven gives you coarser control than a dial marked in degrees — roughly 14°C per step — which is worth remembering before worrying about a three-degree conversion error.
Fan ovens, and why the advice is vague
A fan circulates air, which transfers heat to the food faster than still air at the same temperature, so a fan oven set to the recipe's number will cook hotter and faster than intended. The standard correction is to drop the setting by about 20°C.
That figure is a convention, not physics. Manufacturers suggest anywhere from 15 to 25°C, some recipes are already written for fan ovens without saying so, and the effect depends on how full the oven is. Treat 20°C as a sensible default and your own results as the authority.
Keeping it in proportion
All of the above concerns differences of a few degrees. Domestic ovens are commonly out by more than that, they overshoot and undershoot as the thermostat cycles, and the temperature differs between the top and bottom shelves. If a bake matters, an oven thermometer is worth more than any amount of conversion precision — it tells you what your oven is actually doing, which no converter can know.
FAQ
Why do you show two different answers?
Because the arithmetic and the cookbook disagree, and both are useful. 350°F converts exactly to 176.67°C, but every recipe pairs 350°F with 180°C — which is really 356°F. The exact figure tells you the truth; the conventional figure tells you what to set the dial to. A converter that only gives you 176.7°C is technically correct and practically useless, since no oven dial has that number.
So is 350°F the same as 180°C?
Not quite — they differ by 6°F, or 3.3°C. They are treated as equivalent because both are round numbers on their respective scales and the difference is smaller than the error in a typical oven. The important thing is that the familiar table is a set of convenient roundings rather than a conversion table, which is why the two columns never quite line up.
Is the rounding error consistent?
No, and that surprises people. It ranges from nearly nothing to ten degrees. 375°F against 190°C is out by only 0.6°C. 350°F against 180°C is out by 3.3°C. 325°F against 170°C is out by 7.2°C in one direction, and 500°F against 250°C is out by 10°C in the other. The conventions were chosen for tidy dial numbers, not for consistency, so there is no single fudge factor to apply.
How do gas marks work?
Gas mark 1 is 275°F and every subsequent mark adds 25°F, so gas mark N is 250 plus 25N degrees Fahrenheit. That gives gas 4 at 350°F, gas 6 at 400°F and gas 8 at 450°F, which matches the standard table exactly. Below gas 1 the scale becomes fractional — gas ½ at 250°F and gas ¼ at 225°F — for the low temperatures used in slow cooking and meringues.
What should I do for a fan oven?
The usual advice is to set it about 20°C below the temperature the recipe gives, because moving air transfers heat more efficiently. That is a convention rather than a physical constant, and manufacturers differ — some suggest 25°C, and some recipes are already written for fan ovens. Gas marks do not apply, since gas ovens are not fan-assisted in the same way. Check your manual if a bake is marginal.
Does any of this precision matter?
Less than you would think. Domestic oven thermostats are commonly out by considerably more than the few degrees these conventions differ by, and the temperature varies from shelf to shelf within the same oven. An oven thermometer will tell you more than any converter. Use the conventional setting, and judge by the food.
How we compare
| Feature | Online Tool Store | A plain °F to °C converter | A printed cookbook chart |
|---|---|---|---|
| Gives the setting your dial actually has | ✓ | ✗ | ✓ |
| Shows the exact figure as well | ✓ | ✓ | ✗ |
| Explains why the two disagree | ✓ | ✗ | ✗ |
| Handles gas marks, including fractions | ✓ | ✗ | ✓ |
| Fan oven adjustment | ✓ | ✗ | Sometimes |
| Works with the book shut and hands floury | Needs a device | Needs a device | ✓ |
| Tells you what your oven is really doing | ✗ | ✗ | ✗ |
The advantage over a plain temperature converter is that this one knows what numbers ovens actually have, and says how far the convention sits from the arithmetic. Neither this nor any chart can tell you what your particular oven is doing — that needs a thermometer inside it.