A warm day in Fahrenheit
- Input
- 25 °C to Fahrenheit.
- Working
- °F = 25 × 9/5 + 32 = 45 + 32 = 77.
- Result
- 25 °C = 77 °F (298.15 K)
Temperature Converter
Convert Celsius, Fahrenheit and Kelvin with the exact formulas and a reference-points table — no offset mistakes, in your browser. Runs entirely in your browser — your numbers never leave this device.
Celsius → Fahrenheit
68 °F
In all three scales: 20 °C · 68 °F · 293.15 K
How it works
°F = °C × 9/5 + 32; °C = (°F − 32) × 5/9; K = °C + 273.15
| Reference point | Celsius | Fahrenheit | Kelvin |
|---|---|---|---|
| Crossover point | −40 °C | −40 °F | 233.15 K |
| Water freezes | 0 °C | 32 °F | 273.15 K |
| Room temperature | 20 °C | 68 °F | 293.15 K |
| Normal body temperature | 37 °C | 98.6 °F | 310.15 K |
| Water boils (sea level) | 100 °C | 212 °F | 373.15 K |
| Moderate oven | 180 °C | 356 °F | 453.15 K |
| Hot oven | 200 °C | 392 °F | 473.15 K |
Temperature is the conversion where a simple multiplier fails, because the scales disagree on both the size of a degree and the position of zero. Celsius and Kelvin use the same degree size but different zeros — water freezes at 0 °C and 273.15 K — so Kelvin = Celsius + 273.15, with no multiplication at all. Fahrenheit uses a smaller degree and a zero set far below freezing, so it needs both operations: °F = °C × 9/5 + 32, and back again with °C = (°F − 32) × 5/9.
The reference points in the table anchor the scales to things you can check: water freezes at 0 °C / 32 °F, boils at 100 °C / 212 °F at sea-level pressure, normal body temperature is about 37 °C / 98.6 °F, and −40 is the one value where Celsius and Fahrenheit read the same number. If a conversion result contradicts those anchors, the formula was applied in the wrong direction.
Oven temperatures are the practical use that catches people out, because a rounded gas mark or a fan-oven adjustment is not the same as the exact conversion. This page gives the exact figure — 180 °C = 356 °F, 350 °F = 176.7 °C — and cookbooks commonly round those to 350 °F and 180 °C respectively when they restate a recipe for the other market. Use the exact figure here, then follow your recipe's own rounding if it gives one.
Worked examples
Body temperature to Celsius
- Input
- 98.6 °F to Celsius.
- Working
- °C = (98.6 − 32) × 5/9 = 66.6 × 5/9 = 37.0.
- Result
- 98.6 °F = 37.0 °C
An oven setting to Celsius
- Input
- 350 °F to Celsius.
- Working
- °C = (350 − 32) × 5/9 = 318 × 5/9 = 176.67.
- Result
- 350 °F = 176.7 °C (often written as 180 °C in recipes)
Frequently asked questions
Why is −40 the same in Celsius and Fahrenheit?
Because the two straight-line scales cross there. Solving °C = (°F − 32) × 5/9 with both values equal gives −40 as the only solution, so −40 °C = −40 °F = 233.15 K. It is a useful check: any converter that does not return −40 for −40 has its formula the wrong way round.
How do I convert oven temperatures quickly?
Use the exact formula, then expect recipes to have rounded it. 180 °C converts to exactly 356 °F, and 200 °C to exactly 392 °F, but cookbooks usually print 350 °F and 400 °F. Fan ovens are a separate adjustment — many recipes suggest lowering the setting — so follow the recipe's fan guidance on top of the converted figure.
Can Kelvin be negative?
No. Zero Kelvin is absolute zero, the lowest possible temperature, equal to −273.15 °C. That is why the Kelvin conversion is a pure offset (K = °C + 273.15) with no negative results: a Celsius figure below −273.15 describes no physical temperature.
What is normal body temperature in each scale?
About 37 °C, which is 37 × 9/5 + 32 = 98.6 °F, and 37 + 273.15 = 310.15 K. Individual readings vary through the day and by measurement site, so treat 37 °C / 98.6 °F as the conventional reference figure rather than a precise personal value.
Is there a quick mental shortcut for weather temperatures?
For rough weather sense, double the Celsius and add 30: 20 °C gives about 70 °F against the exact 68 °F. The shortcut drifts further from the truth as temperatures move away from 10 °C, so use this converter for oven, fever-range or any figure you will act on.
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