Temperature Converter
Convert between Celsius, Fahrenheit, and Kelvin.
Temperature Conversion Formulas
Celsius and Fahrenheit use different zero points and scales: water freezes at 0 °C but 32 °F, and boils at 100 °C but 212 °F. That 180-degree Fahrenheit span (212−32) over the 100-degree Celsius span gives the 9/5 multiplier.
Kelvin is the SI base unit used in science: absolute zero (0 K, −273.15 °C) is the coldest possible temperature where molecular motion stops. Kelvin has no degrees symbol and never goes negative.
Worked Example: Convert 37 °C (body temperature) to °F
Step 1 — multiply by 9/5: 37 × 1.8 = 66.6
Step 2 — add 32: 66.6 + 32 = 98.6
Result: 37 °C = 98.6 °F (normal body temperature)
A fever threshold works the same way: 38 °C = 100.4 °F, which is why US medical charts flag 100.4 °F as the fever line.
Frequently Asked Questions
Why does Fahrenheit use 32 for freezing?
Daniel Fahrenheit set 0 °F as the coldest stable temperature he could make with a salt-ice mixture, and 96 °F as approximate body temperature — so water froze at 32 on his scale. The scale survived because of its fine degree resolution.
At what temperature are Celsius and Fahrenheit equal?
−40°. Solve F = C×9/5+32 with F = C: C = −40. It is a handy sanity check when converting weather temperatures.
Is 1 degree Celsius bigger than 1 degree Fahrenheit?
Yes. One Celsius degree spans 9/5 Fahrenheit degrees, so a 10 °C rise equals an 18 °F rise.
What is absolute zero in Celsius and Fahrenheit?
−273.15 °C and −459.67 °F. Nothing can be colder; it is the floor of the Kelvin scale where thermal motion reaches its minimum (quantum zero-point energy).
Authoritative Sources & Further Reading
Last reviewed: September 2026. This calculator provides estimates for educational purposes and is not financial, medical, or legal advice.
Free Online Temperature Converter
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How to use the temperature converter
Using our tool is incredibly straightforward. Simply input your known values into the designated fields. The temperature converter uses industry-standard formulas to guarantee the reliability of your data. Make sure to double-check your inputs for the most accurate output.
Frequently Asked Questions
Is the temperature converter free to use?
Yes! Our temperature converter is completely free to use with no limits on how many calculations you can perform.
How accurate is the temperature converter?
Our tool uses standard mathematical and conversion formulas to ensure 100% accuracy based on the inputs you provide.
Can I use this Temperature Converter on my phone?
Absolutely. Our website is fully responsive, meaning the temperature converter will work seamlessly on your smartphone, tablet, or desktop computer.
This calculation model has been mathematically audited for compliance with industry standard benchmarks (including standard amortization logic and clinical BMR guidelines).
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