Tool
Oven Temperature Converter
Convert between °F, °C, and UK/EU gas mark, with the standard fan/convection oven adjustment applied automatically for you, every single time.
Oven Temperature Converter
350°F
177°C
Gas 4
A recipe written for a UK audience might specify "gas mark 4"; a European recipe gives you Celsius; most US recipes give Fahrenheit. None of these are the same numbering system, and none of them convert to each other with a clean round number, which is exactly why oven temperature mistakes are common when following a recipe from outside your own country.
This tool converts between Fahrenheit, Celsius, and UK/EU gas mark in any direction, and separately applies the standard fan/convection oven adjustment — because a fan oven circulates heat more efficiently and needs a lower set temperature to hit the same actual baking result as a conventional oven.
It's built for the specific, recurring moment of following a recipe written in a temperature system your oven doesn't use, or owning a fan oven and needing to know how much to knock off a conventional-oven recipe's stated temperature.
How the Oven Temperature Converter works
Fahrenheit-to-Celsius conversion uses the standard fixed formula: °C = (°F − 32) × 5⁄9, and the reverse: °F = °C × 9⁄5 + 32. These are exact unit-conversion facts, not estimates.
Gas mark is different — it's not a linear formula but a lookup table of specific published values (gas mark ¼ through 9), each tied to a rounded Fahrenheit and Celsius equivalent by long-standing UK/EU baking convention. The tool matches your input temperature to the closest gas mark entry in that table rather than trying to compute one mathematically, since gas mark was never designed as a linear scale.
For the fan-oven adjustment, the tool subtracts 25°F (or roughly 20°C) from a conventional-oven recipe temperature — the standard adjustment published by King Arthur Baking and general UK/US conversion references, reflecting that fan-forced air transfers heat to food faster than still air at the same nominal temperature.
Worked example: a UK recipe calling for gas mark 6
Gas mark 6 maps to 200°C and 400°F on the standard table — that's the temperature a conventional (non-fan) UK oven should be set to. If your oven is fan-assisted, the recipe (if it doesn't already say so) implicitly expects you to knock the temperature down: 400°F − 25°F = 375°F, or in Celsius terms, roughly 180°C instead of 200°C.
Going the other direction, if a US recipe calls for 350°F and you only have a gas oven marked in gas marks, the tool converts 350°F to Celsius (≈177°C) and finds the closest gas mark table entry, which is gas mark 4 (180°C / 350°F) — an exact match in this case, since gas mark 4 was specifically calibrated around 350°F.
Edge cases this tool handles correctly
- Temperatures between two gas marks
- Not every Fahrenheit or Celsius value lines up exactly with a gas mark entry — the tool returns the closest one by minimum difference, since gas mark ovens typically don't offer finer control than whole or half marks anyway.
- Applying the fan adjustment twice
- If a recipe already specifies "fan" or "convection," don't apply the −25°F adjustment again — it's meant to convert FROM a conventional-oven temperature, not to be stacked on top of an already-fan-calibrated one.
- Very low and very high temperatures
- The gas mark table only covers ¼ through 9 (110°C–240°C / 225°F–475°F), the practical range of home baking and roasting — temperatures outside that range (like a very low slow-cook setting or a pizza-oven-level high heat) don't have a standard gas mark equivalent and the tool won't force one.
Frequently asked questions
Why isn't gas mark just a simple formula like Fahrenheit-to-Celsius?
Gas mark was never designed as a linear numeric scale the way Fahrenheit and Celsius are — it's a historical UK gas-oven dial numbering convention, so the only accurate way to convert it is against the published lookup table, not a formula.
Is the fan-oven adjustment exact?
It's a widely used, standard rule of thumb (−25°F / −20°C), not a precise physical calculation specific to your exact oven model — different fan ovens vary somewhat in how much more efficiently they transfer heat, so it's a reliable starting point, not a guarantee.
My oven only has Fahrenheit — how do I use a Celsius recipe?
Enter the Celsius temperature and the tool converts it to Fahrenheit using the exact formula, so you can set your oven to the converted number directly.
Does gas mark ¼ mean the lowest possible oven setting?
It's the lowest standard gas mark on the published table (110°C / 225°F), used mainly for very slow cooking like meringues or slow-roasted meats — most home gas ovens can go lower on a "warm" setting, but that's below what gas mark numbering covers.