Fahrenheit to Celsius Converter

Fahrenheit to Celsius — quick reference

The formula, worked line by line

Going from Fahrenheit to Celsius means undoing two things in the right order. Fahrenheit sits 32 degrees higher at the freezing point of water, and its degrees are smaller — 180 of them span freezing to boiling where Celsius uses 100. So you remove the offset first, which puts you on a scale that starts at zero in the right place, and only then shrink the numbers by 100/180, which reduces to 5/9 or about 0.5556.

°C = (°F − 32) × 5/9
°C = (°F − 32) ÷ 1.8
350 °F → 350 − 32 = 318, then 318 × 5/9 = 176.7 °C
For a temperature difference, drop the offset: Δ°C = Δ°F × 5/9

The reciprocal check is worth internalising because it costs nothing. Any °F to °C method must satisfy three points, and the last is the crossover, where the two lines meet.

It is the most diagnostic of the three because it is the only place where a sign error, a dropped offset and a swapped ratio all fail visibly at once. Between those anchors the relationship is perfectly linear, so an answer that falls outside the bracket set by two known points is arithmetic, not physics.

• 32 °F must come out as exactly 0 °C
• 212 °F must come out as exactly 100 °C
• Minus 40 must return minus 40, the one temperature the two scales share

One limit worth stating plainly: the offset belongs to temperatures and not to temperature intervals. A 9 °F rise is a 5 °C rise, not a −12.8 °C anything, so for differences, tolerances and rates per hour you apply the 5/9 factor alone and leave the 32 out of it entirely.

How to use the fahrenheit to celsius converter

Type a Fahrenheit figure and the Celsius equivalent appears as you type, to one decimal place; Swap reverses the direction without retyping the value. This is the outward-facing conversion — you have a Fahrenheit number and the audience, the appliance or the guidance you are checking against is metric.

The four common cases are a thermometer reading you want to compare against health guidance written in Celsius, a US recipe going into a Celsius-marked oven, a US food-safety temperature you need in metric, and telling someone abroad what the weather is actually doing back home.

The order of operations is the reverse of the outbound formula: subtract the 32-degree offset first, then scale by 5/9. Doing it the other way round produces an answer that is wrong by about 17.8 degrees every time, which is enough to matter in every one of those four cases.

The thermometer case is where precision counts most, and where the small Fahrenheit degree misleads people. 98.6 °F is exactly 37.0 °C. Because a Fahrenheit degree is only five ninths of a Celsius degree, differences compress: 102 °F is 38.9 °C and 103 °F is 39.4 °C, so a single Fahrenheit degree carries you most of the way across a Celsius half-degree that guidance may treat differently.

Read all of that as help interpreting a number, not as medical advice — thresholds differ by age, by measurement site and by country, and a reading that worries you is a reason to contact a clinician rather than a converter.

Recipes run the opposite way from the usual complaint: the recipe is American and the oven is marked in Celsius. Celsius ovens generally step in fives, sometimes tens, and the two or three degrees you lose to rounding are smaller than the swing of a domestic oven between thermostat cycles.

If the oven is fan-assisted, standard practice is to drop a further 20 °C after converting. UK recipes may also quote gas marks, and Which? pairs gas mark 4 with 350 °F and 180 °C — a trade convention, since the exact conversion of 350 °F is 176.7 °C.

What are US food-safety temperatures in Celsius?

The fourth case is food safety, where the source figures are almost all American and the kitchen may not be. USDA Food Safety and Inspection Service guidance gives a safe minimum internal temperature for each class of meat, and FDA storage guidance covers the appliances; the ladder below carries each figure in both scales.

The reference table above lists each of these Fahrenheit landmarks with both its exact Celsius value and the rounded figure actually in circulation, because the gap between those two columns is where most confusion lives.

Every Fahrenheit value, worked out

76 common Fahrenheit figures each get their own page, with the answer at full precision, the arithmetic, what rounding costs, and the nearest real-world reference point on the scale.

Questions people ask