The Complete Guide to Oven Temperatures: °C, °F, Gas Mark, Fan & Oven Speak
Every cook, sooner or later, stands in front of a recipe that speaks a different oven language. An American baking blog calls for 350°F. A British grandmother’s handwritten cake recipe says Gas Mark 4. Your own oven — a modern fan-assisted model — only shows Celsius. And then there’s the vintage cookbook that simply instructs you to bake “in a moderate oven” and leaves the rest to faith. An oven temperature converter exists to end this confusion in seconds, but understanding what the numbers actually mean will make you a calmer, more confident cook. This guide walks through every oven scale in use around the world, how they relate to each other, and how to use them in a real kitchen.
The Five Oven Scales You Will Meet
There are five ways a recipe can express oven heat, and all of them appear in this converter. Celsius (°C) is the standard in most of the world — Europe, Asia, Australia, and increasingly the UK — and the scale nearly every modern oven dial uses. Fahrenheit (°F) remains the default in the United States, and in American recipes it is still the only temperature you will ever see. Gas Mark is the old British system for gas ovens, numbered from ¼ up to 9, and it survives because millions of UK kitchens still cook with gas and because classic British recipes were written in it. Fan-assisted (convection) Celsius is the setting you use on a fan oven, where a fan circulates hot air and food cooks faster and more evenly than in a conventional static oven. Finally there are the descriptive terms — very slow, slow, moderate, hot, very hot — the oldest system of all, from the era before thermostats, when a cook judged heat by holding a hand in the oven.
The converter above translates freely between all five. Type 180 into the Celsius box and you instantly learn that it is 350°F, Gas Mark 4, 160°C in a fan oven, and a “moderate” oven. Drag the visual slider and every scale follows. That is the entire job of an oven temperature converter: one input, every answer, no mental arithmetic with a cake in the oven and flour on your hands.
Gas Mark to Celsius: The Full Chart
The gas mark system was standardised in the United Kingdom for gas ovens, and its quirk is that the steps are not even — the gaps between marks widen as the oven gets hotter. The universally used table, the same one baked into this converter, is:
| Gas Mark | °C (conventional) | °F | °C (fan-assisted) |
|---|---|---|---|
| ¼ | 110 | 225 | 90 |
| ½ | 120 | 250 | 100 |
| 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 |
Notice that 140°C is listed as 275°F even though 140°C converts mathematically to 284°F. Oven charts are practical approximations, not physics-lab values — thermostats are not that precise anyway, so charts round to the nearest familiar dial setting. When this converter matches a Celsius value to a gas mark, it picks the nearest mark on this standard table, which is exactly what the printed charts on the inside of British oven doors do.
The Conversions Everyone Searches For
180°C to Fahrenheit in an oven
180°C is 350°F — more precisely 356°F by strict arithmetic, but every oven chart in existence rounds it to 350°F, which is the number on American dials. This is the single most-searched oven conversion in the world because 180°C (Gas Mark 4) is the default baking temperature for cakes, cookies, and casseroles across the UK, Europe and Australia, while 350°F is the default baking temperature across the United States. If you remember only one pair, remember this one: 180°C = 350°F = Gas Mark 4.
350°F to Celsius for an oven
Going the other direction, 350°F converts to 176.7°C, which oven charts round to 175°C or 180°C. In practice, set your Celsius oven to 180°C (or 160°C fan) and you will get identical results to an American recipe’s 350°F. The small rounding difference is far smaller than the natural swing of a home oven’s thermostat, which routinely cycles 10–15°C above and below the set point.
Gas Mark 4 in Celsius
Gas Mark 4 is 180°C conventional, 350°F, and 160°C in a fan oven — the “moderate” oven of classic recipes. It is the workhorse setting: sponge cakes, victoria sandwiches, roast chicken joints, lasagne, and most biscuits all live at Gas Mark 4. If a British recipe gives no temperature at all but says “moderate oven”, Gas Mark 4 is the safe assumption.
Other pairs worth memorising: 200°C = 400°F = Gas Mark 6 (roasting vegetables, pizza bases in a home oven’s upper range); 220°C = 425°F = Gas Mark 7 (crusty bread, roast potatoes); 150°C = 300°F = Gas Mark 2 (slow braises, meringues at the low end); and 240°C = 475°F = Gas Mark 9 (the “as hot as it goes” setting for thin-crust pizza and searing).
Fan-Assisted Ovens: The −20°C Rule
A fan (convection) oven circulates hot air with a fan at the back of the cavity. Because the moving air strips away the cool boundary layer around food, heat transfers faster and the whole cavity stays at a much more even temperature — no more burnt tray edges with a raw middle. The universal convention, used by manufacturers and recipe writers alike, is to reduce the conventional temperature by 20°C for a fan oven. So a cake recipe written for 180°C conventional becomes 160°C fan; a 200°C roast becomes 180°C fan.
This converter applies the −20°C rule automatically and shows it explicitly, so you always know where the number came from. A few practical notes: the rule is a starting convention, not a law — very sugary bakes can still brown too fast in a fan oven, so check five minutes early the first time you convert a recipe. Food also tends to cook 10–25% faster with the fan on, so start checking doneness earlier than the recipe says. And if your oven has both settings, use conventional (static) heat for delicate custards and tall cakes where a fierce circulating blast can set the outside before the inside has risen — then switch to fan for roasts, traybakes and anything where even browning is the goal.
Descriptive Oven Terms, Decoded
Before thermostats, recipes described heat in words, and those words are still standardised enough to convert. The generally accepted mapping, which this converter’s “Describe My Oven” lookup uses, is: very slow — 140°C / 275°F / Gas 1 (meringues, slow drying); slow — 150°C / 300°F / Gas 2 (rich fruit cakes, braises); moderately slow — 170°C / 325°F / Gas 3 (shortbread, gentle baking); moderate — 180°C / 350°F / Gas 4 (the everyday baking default); moderately hot — 200°C / 400°F / Gas 6 (roasts, puff pastry); hot — 220°C / 425°F / Gas 7 (bread, roast potatoes); very hot — 240°C / 475°F / Gas 9 (pizza, flatbreads). If a recipe says “hot oven” without a number, Gas Mark 7 is the conventional interpretation, and “slow oven” means Gas Mark 2.
Dish-by-Dish: Where Each Classic Lives
Certain dishes cluster around certain temperatures for good physical reasons, and the preset buttons above encode the classics. Sponge and layer cakes bake at 180°C / 350°F / Gas 4 / 160°C fan: hot enough to set the crumb and brown the top, gentle enough that the centre cooks before the outside overbrowns. Crusty bread loaves want 220°C / 425°F / Gas 7 / 200°C fan, ideally with steam for the first ten minutes, because a fierce initial heat gives maximum oven spring before the crust sets. Roast chicken sits at 200°C / 400°F / Gas 6 / 180°C fan, the sweet spot where the skin renders crisp while the breast stays juicy — always verify with a thermometer (74°C / 165°F at the thickest part of the thigh). Thin-crust pizza wants everything your home oven has, typically 240–250°C / 475°F+ / Gas 9, on a preheated stone or steel. Chocolate chip cookies bake at 175–180°C / 350°F / Gas 4: hot enough for crisp edges, brief enough (10–12 minutes) to keep molten centres. Roast beef traditionally starts hot (220°C) for twenty minutes to brown, then drops to 180°C / Gas 4 for the remainder. Lasagne bakes at 190°C / 375°F / Gas 5 / 170°C fan until bubbling. And meringues need a very slow 120°C / 250°F / Gas ½ / 100°C fan for over an hour — they are drying, not baking.
Why Your Oven Lies (and What to Do About It)
Home ovens are routinely 10–25°C off the dial setting, and the dial measures one spot — usually near the thermostat — while your food sits somewhere else entirely. Hot spots near the walls and cool zones near the door are normal. The single best investment for any cook is a cheap standalone oven thermometer hung from the middle rack: check it after a full twenty-minute preheat and you will know your oven’s true offset. If it reads 165°C when the dial says 180°C, simply set 195°C from now on and stop guessing. Always preheat fully — putting food into a still-climbing oven throws off every timing in the recipe. Learn your hot spots by toasting a tray of bread slices and seeing which brown first; rotate trays halfway through baking. And remember that altitude, a dark versus shiny pan, and how full the oven is all shift results by a few degrees, which is why experienced cooks trust look, smell and thermometers over the dial.
A Short History of Gas Marks
The gas mark scale dates to early-20th-century Britain, when gas ovens were regulated by numbered taps rather than thermostats. It was formalised by the industry so that recipes could give repeatable instructions across different manufacturers’ ovens. The numbers run from ¼ to 9 because that matched the useful range of a domestic gas oven’s control. As electric ovens took over and Celsius became the kitchen standard in the UK, gas marks survived through sheer recipe inertia — millions of beloved recipes, from scones to Sunday roasts, were written in them. American recipes never adopted the system, which is why the °F↔Gas Mark conversion is one of the most common cross-Atlantic kitchen questions. Today the marks remain printed inside many UK oven doors, a small piece of culinary heritage that still earns its keep.
Using This Converter in a Real Kitchen
Three workflows cover nearly everything. Converting a recipe: type the number, set the scale the recipe uses, and read off your oven’s scale — the fan offset is applied automatically. Decoding words: use “Describe My Oven” when a recipe says “moderate” or “very hot”. Exploring: drag the visual slider to build intuition for how the scales move together — after a few minutes of play, pairs like 180°C/350°F/Gas 4 will be muscle memory. Your last setting is remembered on the device, so the converter reopens where you left it. Everything runs entirely in your browser: no account, no tracking, no waiting — just temperatures, instantly, forever free.