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Celsius to Fahrenheit Converter – Free Temperature Converter

Convert Celsius to Fahrenheit, Fahrenheit to Celsius, and Kelvin in both directions. This free temperature converter shows all three scales at once, so one entry answers every version of the question.

Convert Temperature

Converted temperature
Celsius–
Fahrenheit–
Kelvin–

How to Use the Temperature Converter

Type the temperature you have and choose its unit — Celsius, Fahrenheit or Kelvin. Press Convert and the tool instantly shows the equivalent value on all three scales, so you don't need a second conversion. This "show everything" design means a recipe that says 180°C immediately also tells you it is 356°F and 453.15 K.

The tool guards against impossible input: any temperature below absolute zero (−273.15°C) is rejected with an explanation, since nothing can be colder than that. Negative values are perfectly fine otherwise — a −10°F Chicago winter morning converts happily to −23.3°C. Results are rounded to two decimals, which is more precision than any household thermometer offers.

The Conversion Formulas

Temperature conversion is arithmetic, not lookup. The three formulas below are all you need, and the calculator applies them automatically:

°F = °C × 9/5 + 32   •   K = °C + 273.15   •   °C = (°F − 32) × 5/9

The 9/5 factor exists because a Celsius degree is bigger than a Fahrenheit degree: between water's freezing and boiling points there are 100 Celsius degrees but 180 Fahrenheit degrees, and 180/100 = 9/5. The +32 is simply an offset, because Fahrenheit starts its scale 32 degrees below water's freezing point. Kelvin is the easiest of all — it uses the same degree size as Celsius but starts at absolute zero, so it is just Celsius shifted by 273.15.

Worked Example

A Phoenix summer afternoon hits 115°F. What is that in Celsius and Kelvin?

StepCalculationResult
1. Subtract 32115 − 3283
2. Multiply by 5/983 × 5 ÷ 946.11°C
3. Add 273.15 for Kelvin46.11 + 273.15319.26 K
4. Reverse check46.11 × 9 ÷ 5 + 32115°F ✓

The reverse check in step 4 is worth doing whenever a number matters: multiply by 9/5, add 32, and you should land exactly back on 115. If you don't, a step was mistyped.

Reference Table — What Most Converters Don't Include

Numbers mean more with context. Here are reference points that matter in daily American life, all three scales side by side:

Reference point°C°FK
Phoenix summer heat46114.8319.15
Body temperature (normal)3798.6310.15
Fever threshold38100.4311.15
Comfortable room temperature2577298.15
Water freezing032273.15
Chicago winter morning−155258.15
Water boiling (sea level)100212373.15

Two memory aids: 37°C = 98.6°F (body temperature) and −40 is the only number where both scales agree, so −40°C = −40°F. If a conversion lands near one of these anchors and feels wrong, re-check your input.

Limitations

The converter assumes standard atmospheric pressure for reference points like boiling — at high altitude (Denver, the Rockies) water boils below 100°C, which the tool does not adjust for. Results are rounded to two decimals, fine for weather, cooking and health, but laboratory work may need more. Finally, the tool converts temperature values, not temperature differences: a "rise of 10°C" is a rise of 18°F, not 50°F — the +32 offset must not be applied to differences, a classic exam mistake this page's formulas deliberately sidestep by always working from absolute values.

Temperature is one conversion; area is the other travellers trip over. Our square feet to square meters guide is the complete walkthrough for rental listings abroad — and for the holiday clips themselves, the Video to GIF Maker turns the best seconds into a shareable loop.

Frequently Asked Questions

What is the formula for Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (1.8) and add 32. For example, 46°C × 9/5 + 32 = 114.8°F (a Phoenix summer day). To go the other way, subtract 32 and multiply by 5/9. This converter applies the same formula instantly for any value, including negative temperatures below freezing.
What is 37°C in Fahrenheit?
37°C equals 98.6°F. This is normal human body temperature. The calculation is 37 × 9/5 + 32 = 66.6 + 32 = 98.6. A fever is generally counted from about 100.4°F (38°C), which is why this conversion comes up so often when a European thermometer meets an American household.
At what temperature do Celsius and Fahrenheit meet?
Celsius and Fahrenheit are equal at -40°. That is, -40°C = -40°F. It is the only point where the two scales give the same number. Below it, the Fahrenheit number is actually smaller than the Celsius one — a curiosity that makes -40 a favorite check value for testing converters and weather apps.
How do I convert Celsius to Kelvin?
Add 273.15 to the Celsius value. For example, 25°C + 273.15 = 298.15 K. Kelvin never uses the degree symbol — you write 298.15 K, not 298.15°K. Zero kelvin is absolute zero, the coldest possible temperature, which is why scientists prefer a scale that starts there and has no negatives.
What is 0°C in Fahrenheit and Kelvin?
0°C is the freezing point of water: it equals 32°F and 273.15 K. The boiling point of water is 100°C, which equals 212°F and 373.15 K. Those two fixed points originally anchored the Celsius scale, which is why so many everyday temperatures land on tidy Celsius numbers.
Why does the US use Fahrenheit?
Fahrenheit was the standard scale in the British Empire before Celsius was adopted, and the US simply never switched. Its 0–100 range roughly covers the weather most Americans experience, which some people find intuitive for weather. Most of science and medicine in the US quietly uses Celsius or Kelvin anyway.

Guides for This Tool

Celsius to Fahrenheit Conversion: Formulas, Examples & Shortcuts

Convert Celsius to Fahrenheit, Fahrenheit to Celsius and Kelvin — the three formulas, a worked recipe and weather example, anchor points like 37°C = 98.6°F,…

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