An oven temperature converter that moves instantly between Celsius (°C), Fahrenheit (°F) and the UK gas mark scale — and also tells you the matching fan-oven setting. It is built for anyone cooking from a recipe written for a different country or a different type of cooker: American recipes in Fahrenheit, older British recipes in gas marks, and modern European recipes in Celsius. Type one value and you get all three equivalents at once, plus a plain-English description of how hot that really is.
How it works
Celsius and Fahrenheit are linked by a simple linear formula, so those two convert exactly. The gas mark scale is different: it is a fixed set of dial positions rather than a continuous unit. Each whole gas mark corresponds to a conventional temperature on the standard UK chart — gas mark 1 is 140 °C, and each step up adds roughly 14 °C until gas 9 at 240 °C. Below gas 1 sit the “cool” fractional marks ¼ and ½, used for meringues and very slow cooking.
This tool stores that reference chart and, when you enter a temperature, it locates your value on the scale and interpolates between the two nearest printed marks to give a sensible gas-mark estimate. It also subtracts 20 °C to suggest a fan-oven setting, because fan ovens circulate hot air and brown food faster, so the usual advice is to drop one gas mark, or about 20 °C, for the same result. A doneness label — from “very cool” through “moderate” to “very hot” — helps you sanity-check whether the converted figure matches the dish you are making.
Formula note
The temperature conversions use:
°F = °C × 9/5 + 32 and °C = (°F − 32) × 5/9
Gas marks are read from the UK reference scale (gas ¼ = 110 °C up to gas 9 = 240 °C). Because that scale is discrete, gas-mark results are interpolated between printed marks rather than produced by a single equation — which is exactly how cookbooks present them.
Worked example
Suppose an American recipe says to bake at 375 °F. Converting to Celsius: (375 − 32) × 5/9 = 190.6 °C, which the chart rounds to 190 °C. On the UK scale that sits at gas mark 5 — a moderately hot oven, good for scones and roast chicken. If you are using a fan oven, set it about 20 °C lower, to roughly 170 °C, so the food does not over-brown. With one entry the converter gives you the Celsius figure, the gas mark and the fan setting together.
Every figure is calculated in your browser — nothing is uploaded or stored.