Fahrenheit to Celsius Converter

Fahrenheit is still the everyday temperature scale in the United States and a handful of other places. Anyone in the UK reading an American recipe, weather forecast, oven manual or fridge spec sheet needs to convert those Fahrenheit numbers into Celsius — the scale used by UK ovens, NHS thermometers and the Met Office.

The formula in plain English: subtract 32 from the Fahrenheit temperature, then multiply by 5 ÷ 9 (which is the same as dividing by 1.8). The −32 accounts for the offset between the two zero points; the × 5/9 rescales because each Fahrenheit degree is smaller than each Celsius degree.

Worked example. A US recipe asks you to preheat the oven to 425 °F. Subtract 32 → 393. Divide by 1.8 → 218 °C. On a UK fan oven, drop another 20 °C to get a setting of around 200 °C fan. Body temperature of 98.6 °F is (98.6 − 32) ÷ 1.8 = 37 °C. A US weather forecast saying "85 °F" is (85 − 32) ÷ 1.8 ≈ 29 °C — a warm summer day in southern England.

Why this matters. American recipes are everywhere on the internet, and UK ovens are calibrated only in Celsius. Setting a UK oven to 425 (taking the Fahrenheit number at face value) is dangerous — most domestic ovens max out around 250 °C and the recipe would be impossible to follow. Doing the conversion turns 425 °F into a sensible 218 °C, which any UK oven can manage.

When to use it. Following American baking and cooking recipes, decoding US weather forecasts when travelling, reading imported medical thermometers, and comparing fridge or freezer guidance from US food-safety sources.

When not to rely on memory alone. The offset of 32 makes the conversion non-trivial — there's no "just halve it" shortcut that works at cold temperatures. Always use the proper formula when the result matters (cooking, fevers, food storage).

Common mistakes. Halving the Fahrenheit number without subtracting 32 first (this is roughly right around 100 °F but wildly wrong below freezing). Forgetting that fan ovens run hotter than conventional ovens at the same dial setting, so drop the converted figure by 15–20 °C if the recipe assumed a non-fan oven. Confusing "180 °C fan" with "180 °C conventional" — the cooked result is very different.