Fidamen

Convert Celsius to Kelvin – Temperature Converter

This tool converts a temperature value in degrees Celsius (°C) to kelvin (K). The conversion is a fixed linear offset and is exact by definition: one kelvin has the same magnitude as one degree Celsius, only the zero point differs.

Use the converter for scientific, engineering, educational, and workplace calculations. For measurements used in compliance or calibration activities, follow laboratory traceability and calibration best practices referenced below.

Updated Nov 28, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 758ea7abe2ac • Reviewed by Fidamen Standards Committee

Interactive Converter

Convert between celsius and kelvin with precision rounding.

Quick reference table

CelsiusKelvin
1 °C274.15 K
5 °C278.15 K
10 °C283.15 K
25 °C298.15 K
50 °C323.15 K
100 °C373.15 K

Methodology

The conversion is a dimension-preserving linear offset: kelvin equals the Celsius temperature plus 273.15. This is an exact relationship used in engineering and science and consistent with international measurement practice.

When using measured temperatures rather than calculated values, consider sensor uncertainty, instrument calibration, and environmental effects. Calibration and uncertainty statements should follow recognized standards such as ISO/IEC 17025 for calibration laboratories and the international temperature scales maintained by national metrology institutes.

This converter provides mathematical conversion only. For regulatory, safety, or compliance use, pair the numeric conversion with calibrated instruments and documented traceability to national standards (for example, NIST or the national metrology institute in your jurisdiction).

Key takeaways

Conversion is exact: add 273.15 to °C to obtain K.

Kelvin uses no degree symbol; the unit symbol is K.

For measured temperatures, account for instrument uncertainty and calibration traceability.

Worked examples

25 °C → 25 + 273.15 = 298.15 K

-273.15 °C → -273.15 + 273.15 = 0 K (absolute zero)

100 °C → 100 + 273.15 = 373.15 K

F.A.Q.

Is the conversion between Celsius and kelvin exact?

Yes. The size of one kelvin equals one degree Celsius and the offset is exactly 273.15, so K = °C + 273.15 is exact as a mathematical relation between the two scales.

Can Kelvin be negative?

No. By definition of the thermodynamic temperature scale, 0 K is absolute zero (equivalent to -273.15 °C). Values below 0 K are not physically meaningful on the kelvin scale used here.

Should I round results and how many decimals are appropriate?

Rounding depends on the measurement or calculation context. For display, two decimal places (e.g., 298.15 K) is common. For scientific work, match rounding to the uncertainty of your measured or reported temperature and follow your discipline's significant-figure conventions.

Does this converter account for sensor error or calibration uncertainty?

No. This converter performs the mathematical unit conversion only. When converting measured temperatures for compliance, record instrument uncertainty, calibration date, and traceability to a recognized standard such as ISO/IEC 17025 or national metrology institute references.

Why is the offset 273.15?

The offset historically ties to the Celsius scale definition based on the triple point of water and the relationship established between the Celsius and kelvin scales. Modern definitions preserve the fixed offset so that the conversion remains exact.

What symbol should I use for kelvin?

Use the uppercase letter K without a degree symbol. For Celsius use °C.

Sources & citations

Further resources

Versioning & Change Control

Audit record (versions, QA runs, reviewer sign-off, and evidence).

Record ID: 758ea7abe2ac

What changed (latest)

v1.0.0 • 2025-11-28 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Public QA status

PASS — golden 25 + edge 120

Last run: 2026-01-23 • Run: golden-edge-2026-01-23

Engine

v1.0.0

Data

Baseline (no external datasets)

Content

v1.0.0

UI

v1.0.0

Governance

Last updated: Nov 28, 2025

Reviewed by: Fidamen Standards Committee (Review board)

Credentials: Internal QA

Risk level: low

Reviewer profile (entity)

Fidamen Standards Committee

Review board

Internal QA

Entity ID: https://fidamen.com/reviewers/fidamen-standards-committee#person

Semantic versioning

  • MAJOR: Calculation outputs can change for the same inputs (formula, rounding policy, assumptions).
  • MINOR: New features or fields that do not change existing outputs for the same inputs.
  • PATCH: Bug fixes, copy edits, or accessibility changes that do not change intended outputs except for previously incorrect cases.

Review protocol

  • Verify formulas and unit definitions against primary standards or datasets.
  • Run golden-case regression suite and edge-case suite.
  • Record reviewer sign-off with credentials and scope.
  • Document assumptions, limitations, and jurisdiction applicability.

Assumptions & limitations

  • Uses exact unit definitions from the Fidamen conversion library.
  • Internal calculations use double precision; display rounding follows the unit's configured decimal places.
  • Not a substitute for calibrated instruments in regulated contexts.
  • Jurisdiction-specific rules may require official guidance.

Change log

v1.0.0 • 2025-11-28 • MINOR

Initial publication and governance baseline.

Why: Published with reviewed formulas, unit definitions, and UX controls.

Areas: engine, content, ui • Reviewer: Fidamen Standards Committee • Entry ID: 981f201e7a59