Which units does this temperature converter use?
Celsius, fahrenheit, and kelvin only. Enter one value, one from-unit, and one to-unit. Length, weight, and cooking units are not used on this tool.
Temperature Converter
Convert one temperature into another across celsius, fahrenheit, and kelvin. Enter one value, one from-unit, and one to-unit. The page converts via Celsius as the pivot in a single exact step, then rounds the display half-up to two decimals. Zero celsius is 32.00 fahrenheit and 273.15 kelvin. This is an everyday temperature estimate only, not a medical thermometer reading and not a lab measurement. Length, weight, and cooking units are not on this tool.
How temperature conversion works
Every temperature on this page is turned into Celsius with an exact formula, then into the unit you asked for. From fahrenheit: (F − 32) × 5/9. From kelvin: K − 273.15. To fahrenheit: C × 9/5 + 32. To kelvin: C + 273.15. Same-unit values stay as entered.
The exact result is computed in one step from that Celsius pivot. The page rounds that exact result half-up to two decimals. It does not round an intermediate unit and then convert again. Zero celsius is exactly 32 fahrenheit (32.00) and exactly 273.15 kelvin. One hundred celsius is exactly 212 fahrenheit (212.00). Thirty-two fahrenheit is exactly 0 celsius (0.00). Minus forty celsius is exactly −40 fahrenheit (−40.00). Minus ten celsius is exactly 14 fahrenheit (14.00). One fahrenheit is exactly (1 − 32) × 5/9 + 273.15 = 255.9277… kelvin, which displays as 255.93.
Absolute zero is allowed: −459.67 fahrenheit and −273.15 celsius and 0 kelvin. Anything colder is rejected. Empty and non-numeric values are rejected. This tool does not convert length, weight, or cooking units.
Worked example
0 celsius converts to 32.00 fahrenheit. The same zero is exactly 273.15 kelvin. One hundred celsius is 212.00 fahrenheit. One fahrenheit is 255.93 kelvin from the exact 255.9277… value. This is an everyday temperature estimate only, not a medical thermometer reading and not a lab measurement.
Formula
Convert via Celsius as the pivot in one exact step. C from F: (F − 32) × 5/9. C from K: K − 273.15. F from C: C × 9/5 + 32. K from C: C + 273.15. Display = round2(exact result), half-up to 2 decimals. Do not chain a rounded intermediate. round2 is the same helper as length-converter / weight-converter / gpa/concrete round2 and discount roundMoney.
- v
- The temperature you enter. Zero celsius is allowed. Negatives are allowed at or above absolute zero. Empty and non-numeric values are rejected.
- C
- Exact Celsius pivot. Computed once from the from-unit, then used once to reach the to-unit.
- round2
- Half-up to 2 decimals, applied once to the exact result. Not banker's rounding.
Disclaimer
Everyday temperature estimate only, not a medical thermometer reading and not a lab measurement. This page converts celsius, fahrenheit, and kelvin via an exact Celsius pivot and rounds the display half-up to two decimals. It does not convert length, weight, or cooking units.
Frequently asked questions
Why is 0 celsius both 32.00 fahrenheit and 273.15 kelvin?
Zero celsius times 9/5 plus 32 is exactly 32 fahrenheit, which displays as 32.00. Zero celsius plus 273.15 is exactly 273.15 kelvin. The page converts via that Celsius pivot in one step and rounds the display half-up to two decimals.
Why does 100 celsius show 212.00 fahrenheit?
One hundred celsius times 9/5 plus 32 is exactly 212 fahrenheit, which displays as 212.00. The page does not round an intermediate unit and convert again.
Why does 1 fahrenheit show 255.93 kelvin?
One fahrenheit converts as (1 − 32) × 5/9 + 273.15, which is exactly 255.9277… kelvin. Half-up to two decimals is 255.93, not 255.92. The page rounds that exact result once.
Are negative temperatures allowed?
Yes, when the value is at or above absolute zero. Zero celsius is allowed. −40 celsius displays as −40.00 fahrenheit. −10 celsius displays as 14.00 fahrenheit. −459.67 fahrenheit is allowed (exactly 0 kelvin). Values below absolute zero (kelvin less than 0, celsius less than −273.15, or fahrenheit less than −459.67) are rejected. Empty and non-numeric values are rejected too.
Is this a medical thermometer or lab measurement?
No. Everyday temperature estimate only, not a medical thermometer reading and not a lab measurement. It uses the exact Celsius-pivot formulas on this page and rounds the display to two decimals.