Convert Celsius to Kelvin – Free Online °C to K Calculator

Convert °C to K as you type.

Temp Converter Australia

1 °C = 274.15 K

Reference for one unit; displayed values may be rounded.

Enter Celsius

°C

Celsius

Use a dot or comma for decimals, without thousands separators.

Result in Kelvin

Kelvin

Decimal places

Display rounding does not improve the accuracy of your original measurement. Very large or very small results use scientific notation.

Method and source

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 Aussie readings run from winter lows around -10° in Canberra and the Snowy Mountains to summer tops above 45° in the Outback, making Celsius the daily temperature language of the Bureau of Meteorology's forecasts.

Where it is used: Weather forecasts from the BOM, Aussie kitchens and barbies, GP clinics and chemists; 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 at CSIRO and university labs, 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

Select a value to use it in the calculator.

Celsius (°C)	Kelvin (K)
	0 K
	77.15 K
	194.65 K
	233.15 K
	255.15 K
	273.15 K
	283.15 K
	293.15 K
	298.15 K
	303.15 K
	310.15 K
	323.15 K
	373.15 K
	423.15 K
	473.15 K
	573.15 K
	773.15 K
	1273.15 K
	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 tutes and assignments

Gas-law equations such as PV = nRT only accept absolute temperature. Typing 27°C on a muggy Brisbane arvo gives 300.15 K instantly, and a chest freezer at -18°C becomes 255.15 K without touching a calculator.

Cryogenic storage and shipping

Dewar specs and cell-banking protocols quote temperatures in Kelvin — liquid nitrogen sits near 77 K and an ultra-low freezer at -80°C is 193.15 K. From IVF clinics to CSIRO sample banks and vaccine cold chains heading to remote communities, converting Celsius readings keeps inventory logs consistent.

Reading phase diagrams

Metallurgy references plot melting curves in Kelvin: iron melts at 1811.15 K and aluminium at 933.15 K, while a foundry pyrometer reports 1538°C. Whether you're studying materials engineering or working near the smelters at Whyalla, Portland or Bell Bay, this converter bridges the two instantly.

Writing lab reports in SI units

Journals and uni labs 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 — so your prac report meets SI standards every time.

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How to Use

1

Enter the Temperature in Celsius

Type the Celsius value — for example, enter 27 for a thermodynamics tute question set at 27°C, a typical muggy Brisbane summer day
2

See the Kelvin Result

The absolute temperature appears instantly: 27°C = 300.15 K, ready to plug straight into PV = nRT
3

Copy or Swap

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

Check the Reference Table

Browse common anchors like 0°C = 273.15 K (a frosty Canberra morning — water freezes) 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 halfway through a tute problem or prac calculation

Exact SI Definition

Uses the fixed offset K = °C + 273.15, so 0°C returns exactly 273.15 K with no rounding drift in your prac reports

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) for smelter and foundry specs

Swap with One Click

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

Free & No Signup

Unlimited conversions for uni assignments, prac notebooks, and research projects — always free, no account needed

Runs Locally

Every calculation happens right in your browser. No temperature data ever leaves your device or hits a 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 — a pleasant spring afternoon in Perth. 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 — the sort of reading you'll see on winter mornings in Canberra, Orange, or the Victorian high country, 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. Even the Antarctic winter nights logged by Australian research stations come nowhere near it, bottoming out around 184 K (-89°C) at the coldest ever recorded.

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. Outside the textbook, it's a cracking day on the Adelaide parklands.

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 physiology and biomedical literature, and fever thresholds such as 38°C = 311.15 K are reported the same way. And on a scorching January afternoon, the air in Penrith can hit 37°C too — that's 310.15 K outside.

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 — the standard throughout Australian physics and engineering courses.

What is 100°C in Kelvin?

100°C equals 373.15 K, the boiling point of water at sea level. Steam tables and engineering thermodynamics references list saturated steam properties starting at exactly 373.15 K. Worth noting for the mountains: up at Thredbo, roughly 1,900 metres above sea level, the kettle boils closer to 93°C (366 K).

About Our 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're tackling HSC Physics or VCE Chemistry, working through first-year thermodynamics at uni, checking cryogenic storage specs for vaccine freezers, or dealing with heat treatment in the mining and smelting game, 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 Converting Celsius to Kelvin

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 workhorse of IVF clinics and uni labs across Australia — dry ice sublimates at 194.65 K (-78.5°C), and an ultra-low vaccine freezer at -80°C holds 193.15 K.

Materials data: aluminium melts at 933.15 K (660°C) — the metal behind Australia's smelters at Tomago, Portland and Bell Bay — gold from the Kalgoorlie Super Pit melts at about 1337 K (1064°C), iron at 1811.15 K (1538°C), 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 source of wrong answers in exams and pracs.

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