Celsius to Kelvin Calculator — Convert °C to K Instantly
Our free Celsius to Kelvin calculator adds 273.15 for you and delivers instant, exact results — perfect for chemistry homework, lab reports, and engineering problem sets.
Ultimate Temperature ConverterThe quick answer for 1 Celsius — type any value below for the exact result
Celsius
Kelvin
Celsius to Kelvin Conversion Formula
Celsius and Kelvin Explained
Celsius (c)
The Celsius scale (symbol °C) measures temperature with water freezing at 0° and boiling at 100° at one standard atmosphere. Each Celsius degree is exactly the same interval as one kelvin, so the scale differs from Kelvin only by the fixed offset of 273.15. Although Americans use Fahrenheit for weather and cooking, Celsius is the working scale inside US classrooms, laboratories, and hospitals — a Phoenix summer hits about 45°C, and a Minnesota winter can plunge past -30°C.
Where it is used: Science courses from middle school through college, medical charting, laboratory work, and international travel — anywhere American daily life meets global science standards.
Origin: Swedish astronomer Anders Celsius proposed the scale in 1742 with 0° at boiling and 100° at freezing; it was reversed to the modern direction shortly after his death. The US scientific community standardized on Celsius long ago, even as everyday weather forecasts stayed Fahrenheit.
Kelvin (k)
The kelvin (symbol K, never °K) is the SI base unit of thermodynamic temperature, defined since 2019 by an exact value of the Boltzmann constant. Zero kelvin is absolute zero — the point of minimum thermal motion — and its degrees are the same size as Celsius degrees: water freezes at 273.15 K and boils at 373.15 K. The scale spans from millikelvin quantum experiments to stellar interiors at millions of kelvin.
Where it is used: Physics, chemistry, and engineering wherever absolute temperature matters: gas laws, radiation laws, cryogenics, astronomy, and materials science. US engineering thermodynamics texts sometimes pair it with the Rankine scale, its Fahrenheit-based counterpart.
Origin: William Thomson (Lord Kelvin) proposed an absolute temperature scale in 1848; the kelvin became an SI base unit in 1960 and dropped its degree sign in 1968.
Celsius to Kelvin Conversion Table
| Celsius (c) | Kelvin (k) |
|---|---|
| -273.15 c | 0 k |
| -196 c | 77.15 k |
| -78.5 c | 194.65 k |
| -40 c | 233.15 k |
| -18 c | 255.15 k |
| 0 c | 273.15 k |
| 10 c | 283.15 k |
| 20 c | 293.15 k |
| 25 c | 298.15 k |
| 30 c | 303.15 k |
| 37 c | 310.15 k |
| 50 c | 323.15 k |
| 100 c | 373.15 k |
| 150 c | 423.15 k |
| 200 c | 473.15 k |
| 300 c | 573.15 k |
| 500 c | 773.15 k |
| 1000 c | 1273.15 k |
| 1538 c | 1811.15 k |
Kelvin to Celsius Conversion Table
| Kelvin (k) | Celsius (c) |
|---|---|
| 0 k | -273.15 c |
| 4.2 k | -268.95 c |
| 77 k | -196.15 c |
| 194.65 k | -78.5 c |
| 233.15 k | -40 c |
| 273.15 k | 0 c |
| 288.15 k | 15 c |
| 293.15 k | 20 c |
| 298.15 k | 25 c |
| 300 k | 26.85 c |
| 310.15 k | 37 c |
| 373.15 k | 100 c |
| 1811 k | 1537.85 c |
Celsius to Kelvin in Everyday Objects
Common real-world examples that make Celsius and Kelvin easy to picture at a glance.
| Celsius (c) | Kelvin (k) | |
|---|---|---|
| Water freezing point (32°F) | 0 c | 273.15 k |
| Water boiling point (212°F) | 100 c | 373.15 k |
| Standard lab temperature (77°F) | 25 c | 298.15 k |
| Body temperature (98.6°F) | 37 c | 310.15 k |
| Dry ice sublimation (-109.3°F) | -78.5 c | 194.65 k |
| Liquid nitrogen boiling (-320°F) | -196.15 c | 77 k |
| Iron melting point (2,800°F) | 1538 c | 1811.15 k |
| Absolute zero (-459.67°F) | -273.15 c | 0 k |
When You Need Celsius to Kelvin Conversions
Thermodynamics problem sets
Gas-law equations like PV = nRT only accept absolute temperature. Type 27°C to get 300.15 K instantly, and a chest freezer at -18°C (about the 0°F setting) becomes 255.15 K without touching a calculator.
Cryogenic storage and shipping
Dewar specs and biobank protocols quote temperatures in Kelvin — liquid nitrogen sits near 77 K and an ultra-low freezer at -80°C holds 193.15 K — so converting Celsius readings keeps inventory logs consistent, from university labs to pharma cold chains.
Reading phase diagrams
Metallurgy references plot melting curves in Kelvin: iron melts at 1811.15 K and aluminum at 933.15 K, while a foundry pyrometer reports 1538°C — this calculator bridges the two systems instantly.
Writing lab reports in SI units
US journals and university courses require absolute temperatures: an experiment run at room temperature of 23°C (73.4°F) is reported as 296.15 K, and a water bath held at 60°C as 333.15 K.
Related Temperature Conversions
How to Use
-
1
Enter the Temperature in Celsius
Type the Celsius value — say, 27 for a gas-law problem set at 27°C, a warm afternoon in Houston
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2
See the Kelvin Result
The absolute temperature appears instantly: 27°C = 300.15 K, ready to plug straight into PV = nRT
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3
Copy or Swap
Copy the result for your homework or click Swap to convert Kelvin back to Celsius
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4
Check the Reference Table
Browse common anchors like 0°C = 273.15 K (water freezes, 32°F) or 100°C = 373.15 K (water boils, 212°F)
Why Use Be Converter?
Instant Absolute-Temperature Results
Kelvin results update in real time as you type — no pausing mid-problem to add 273.15 by hand
Exact SI Definition
Applies the fixed offset K = °C + 273.15, so 0°C returns exactly 273.15 K — no rounding drift on your lab report or homework
Scientific Reference Table
Key anchors at a glance — absolute zero (-273.15°C = 0 K), liquid nitrogen (-196°C = 77.15 K), dry ice (-78.5°C = 194.65 K), and iron melting (1538°C = 1811.15 K)
Swap with One Click
Flip to Kelvin-to-Celsius instantly — handy when a textbook quotes 298 K but your bench thermometer reads in Celsius
Free & No Signup
Unlimited conversions for problem sets, lab notebooks, and research papers — always free, no account required
Runs Locally
Every calculation happens right in your browser. No temperature data ever leaves your device
Frequently Asked Questions
What is the formula to convert Celsius to Kelvin?
What is 0°C in Kelvin?
What is absolute zero on the Celsius scale?
What is 25°C in Kelvin?
Is a Kelvin degree the same size as a Celsius degree?
What is 37°C in Kelvin?
Why do scientists use Kelvin instead of Celsius?
What is 100°C in Kelvin?
About Celsius to Kelvin Converter
Our free Celsius to Kelvin calculator applies the exact SI offset of 273.15 to any value you enter, converting everyday Celsius readings into absolute temperatures for physics, chemistry, and engineering coursework. While Fahrenheit rules American weather reports and kitchen ovens, science runs on SI units — whether you're working through gas-law problems in AP Chemistry, reading a phase diagram in a materials science class, checking cryogenic freezer specs for a research lab, or writing up a lab report for your university, this tool delivers instant, exact results. The Celsius scale, introduced by Anders Celsius in 1742, and the Kelvin scale, proposed by Lord Kelvin in 1848 and now an SI base unit recognized by NIST, use the same size degrees — they differ only by the fixed 273.15 offset.
Expert Tips for Celsius to Kelvin Conversion
The conversion is pure addition: K = °C + 273.15. Never multiply by any factor — unlike Fahrenheit, temperature intervals are already identical in size (Δ1°C = Δ1 K).
Memorize the science anchors with their Fahrenheit twins: 0°C = 273.15 K (freezing, 32°F), 25°C = 298.15 K (thermodynamic standard, 77°F), 37°C = 310.15 K (body temperature, 98.6°F), 100°C = 373.15 K (boiling, 212°F).
Cryogenic checkpoints: liquid nitrogen boils at about 77 K (-196°C, or -320°F), dry ice sublimates at 194.65 K (-78.5°C, or -109.3°F), and an ultra-low lab freezer at -80°C holds steady at 193.15 K.
Materials data for shop and lab: aluminum melts at 933.15 K (660°C / 1,220°F), gold at about 1,337 K (1,064°C / 1,947°F), iron at 1,811.15 K (1,538°C / 2,800°F), and tungsten at 3,695.15 K (3,422°C / 6,192°F).
Keep the full 273.15 constant through every intermediate step. Since the 2019 SI redefinition the offset is exactly 273.15, and dropping the .15 early is a classic way to lose points on graded problem sets.