Celsius to Kelvin Converter – Free Online °C to K Calculator for Students & Engineers

Convert Celsius to Kelvin instantly with our free online °C to K calculator — ideal for JEE, NEET and CBSE students, engineers, and lab professionals across India.

Temperature Converter - Celsius to Fahrenheit & Kelvin

1 c = 274.15 k

The quick answer for 1 Celsius — type any value below for the exact result

Enter Celsius

Celsius

Result in Kelvin

Kelvin

Celsius to Kelvin Conversion Formula

K = °C + 273.15

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. Everyday readings in India span from -30°C or lower in Dras and Leh during winter to 45°C and beyond in Delhi and Chhattisgarh summers, making Celsius the daily temperature language of IMD bulletins, school lessons, and kitchens alike.

Where it is used: Weather forecasts from the India Meteorological Department, kitchens (checking milk before it boils over, judging oil temperature for frying), and clinics across India; science courses also use it for everyday measurements before converting into SI units.

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.

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 (including ISRO's cryogenic upper stages), astronomy, and materials science.

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	0 c	273.15 k
Water boiling point	100 c	373.15 k
Standard lab temperature	25 c	298.15 k
Human body temperature	37 c	310.15 k
Dry ice sublimation	-78.5 c	194.65 k
Liquid nitrogen boiling	-196.15 c	77 k
Iron melting point	1538 c	1811.15 k
Absolute zero	-273.15 c	0 k

When You Need Celsius to Kelvin Conversions

Thermodynamics numericals and entrance exams

Gas-law equations such as PV = nRT only accept absolute temperature. Typing 27°C gives 300.15 K instantly, and a deep freezer at -18°C becomes 255.15 K — perfect for last-minute revision before NEET or JEE.

Vaccine cold chains and cryogenic storage

Dewar flasks, cell-banking protocols, and India's immunisation cold chain all quote temperatures precisely — liquid nitrogen sits near 77 K, an ultra-low freezer at -80°C is 193.15 K, and standard vaccine storage of 2-8°C equals 275.15-281.15 K — so converting Celsius readings keeps inventory logs consistent.

Reading phase diagrams and foundry work

Metallurgy references plot melting curves in Kelvin: iron melts at 1811.15 K and aluminium at 933.15 K, while a pyrometer in a Rajkot or Coimbatore foundry reports 1538°C — this converter bridges the two instantly.

Writing lab reports in SI units

University journals and IIT, NIT lab records require absolute temperatures: an experiment run at room conditions of 23°C is reported as 296.15 K, and a water bath held at 60°C as 333.15 K.

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How to Use

1

Enter the Temperature in Celsius

Type the Celsius value — for example, enter 27 for a gas-law numerical set at 27°C, a favourite condition in JEE Main and Class 11 physics questions
2

See the Kelvin Result

The absolute temperature appears instantly: 27°C = 300.15 K, ready to plug into PV = nRT in your physics or chemistry answer
3

Copy or Swap

Copy the result or click Swap to convert Kelvin back to Celsius
4

Check the Reference Table

Browse common anchors like 0°C = 273.15 K (water freezes — think Dal Lake on a January night) or 100°C = 373.15 K (water boils at sea level)

Why Use Be Converter?

Instant Absolute-Scale Conversion

Kelvin results appear in real time as you type — no need to add 273.15 by hand midway through a JEE numerical or a lab journal entry

Exact SI Definition

Uses the fixed offset K = °C + 273.15, so 0°C returns exactly 273.15 K with no rounding drift in CBSE practical files and university lab records

Scientific Reference Table

Key anchors at a glance — absolute zero (-273.15°C = 0 K), liquid nitrogen (-196°C = 77.15 K), and iron melting (1538°C = 1811.15 K), the same melt temperature behind India's steel plants

Swap with One Click

Flip to Kelvin to Celsius instantly — handy when a research paper reports 298 K and your college bench thermometer reads 24.85°C

Free & No Signup

Unlimited conversions for board exam preparation, coaching-class problem sets, college lab journals, and research — always free (₹0), no account needed

Runs Locally

Every calculation happens in your browser. No temperature data is sent to any server

Frequently Asked Questions

What is the formula to convert Celsius to Kelvin?

The formula is K = °C + 273.15. Simply add 273.15 to the Celsius value. For example, 20°C + 273.15 = 293.15 K — the kind of direct numerical that appears in Class 11 physics and JEE Main papers. There is no multiplication involved — the two scales use identical-sized degrees.

What is 0°C in Kelvin?

0°C equals 273.15 K. This is the freezing point of water at standard atmospheric pressure — think of shallow ponds icing over in Srinagar or Shimla during a cold wave — and one of the most-used reference points in science.

What is absolute zero on the Celsius scale?

Absolute zero is 0 K, which equals -273.15°C. It is the theoretical point where particles reach minimum thermal motion — no substance can be cooled below it.

What is 25°C in Kelvin?

25°C equals 298.15 K. This is the standard reference temperature in thermodynamics tables, so the value 298.15 K appears constantly in chemistry problems and property tables — and it is close to a pleasant Bengaluru afternoon all year round.

Is a Kelvin degree the same size as a Celsius degree?

Yes. One kelvin and one Celsius degree represent the same temperature interval, so a rise of 10°C is exactly a rise of 10 K. The scales differ only by the 273.15 offset, which is why conversion is simple addition.

What is 37°C in Kelvin?

37°C equals 310.15 K. Normal human body temperature is often quoted as 310 K in medical literature, and the 38°C = 311.15 K mark is the fever threshold Indian doctors monitor closely during seasonal dengue and flu outbreaks.

Why do scientists use Kelvin instead of Celsius?

Because Kelvin is an absolute scale: 0 K is absolute zero, so temperature is directly proportional to thermal energy. Formulas such as the ideal gas law (PV = nRT), the Stefan-Boltzmann law, and Arrhenius rate equations only give correct results when temperature is entered in Kelvin — a point examiners check closely in JEE Advanced and GATE solutions.

What is 100°C in Kelvin?

100°C equals 373.15 K, the boiling point of water at sea level, as in Mumbai or Chennai. Note that at high-altitude towns such as Leh or Mussoorie, water boils below 100°C because of lower atmospheric pressure. Steam tables and engineering thermodynamics references list saturated steam properties starting at exactly 373.15 K.

About Celsius to Kelvin Converter

Our free online Celsius to Kelvin converter adds the exact SI offset of 273.15 to any value you enter, turning everyday Celsius readings into absolute temperatures for physics, chemistry, and engineering. Whether you are among the lakhs of Class 11 and 12 students preparing thermodynamics numericals for JEE or NEET, a B.Tech student at an IIT, NIT or state engineering college drafting heat-transfer lab journals, a technician logging vaccine cold-chain temperatures between 2°C and 8°C, or a foundry engineer in Coimbatore or Rajkot cross-checking melt points, this tool gives 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, 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 Celsius by any factor — temperature intervals are already identical in size (Δ1°C = Δ1 K).

Memorise the science anchors: 0°C = 273.15 K (freezing), 25°C = 298.15 K (thermodynamic standard), 37°C = 310.15 K (body temperature), 100°C = 373.15 K (boiling).

Cryogenic checkpoints: liquid nitrogen boils at about 77 K (-196°C) — the same coolant behind the liquid-nitrogen ice cream counters in metro-city malls — dry ice sublimates at 194.65 K (-78.5°C), and an ultra-low lab freezer at -80°C holds 193.15 K.

Materials data: aluminium melts at 933.15 K (660°C), gold at about 1337 K (1064°C) — useful knowledge for the 22-karat jewellery trade — iron at 1811.15 K (1538°C), the working melt of Bhilai and Jamshedpur steel plants, and tungsten at 3695.15 K (3422°C).

Keep the full 273.15 constant through intermediate steps. Since the 2019 SI redefinition the offset is exactly 273.15, and dropping the .15 early is a classic way to lose marks in board practicals and JEE answer scripts.