Celsius to Kelvin Converter
Convert between Celsius and Kelvin with hard absolute-zero checks. Runs locally in your browser.
Trust summary CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance
- Input interpretation
- Enter values to calculate.
- Result
- —
- Assurance
- Engineering
- Declared partition coverage
- PASS · 2/2 declared partitions (celsius-kelvin, invalid-domain) · Matrix
- Known limitations
- Absolute zero floor
- Core CVP does not include live graph, viewport, or pointer interaction.
- Model
- Celsius ↔ Kelvin conversion.
- Scope
- ITS-90 offset 273.15
- Verification
- Engine tested · Source checked · v1.0.0 · CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· View Manifest · CVP overview · Specification
- Versions
- Calculation 1.0.0 · CVP protocol 1.0.0-proposed
- CVP identity
- 2/2 property · digest 599cc260cf9c
- Legacy regression
- 6/6 tests · Production surface contract 4/4
- Reference
- O1 model · O2 expected_values · O2 numerical_behavior
- Interfaces
- PASS · UI (SSR) / REST / MCP
- Supplemental domain review
- Internal · Pass
- Named expert review
- Not performed
- CVP suite
- 1/1 golden · 2/2 CVP boundary · 2/2 invalid · 2/2 property · 1/1 cross-interface · 1/1 CVP contract · Manifest
- Sources
- SI temperature units
- NIST / SI temperature
- Evidence
- 2 legacy golden · 2 legacy boundary · legacy regression suite · 1/1 oracle-backed golden · 2/2 invalid · Artifact integrity PASS · CalculatorX electrical review
- Semantic contract
- PASS
Full verification
Formulas
Core equations used by this calculator.
How to use
Choose °C → K or K → °C
Same offset conversion in either direction.
Enter the temperature
Kelvin must be ≥ 0 when converting from K.
Read the converted value
K = °C + 273.15 (exact offset used by this tool).
Example calculations
Common configurations with formula and result.
25 °C
room temperature
Celsius to Kelvin converter specification
Version 1.0.0 · Engine tested · Supplemental domain review · Internal · 2026-08-09
- Engine tested 6/6 tests · Production surface contract 4/4
- Supplemental domain review Internal · Pass · 2026-08-09
- Named expert review Not performed
- Calculation version 1.0.0
Review policy · Evidence · Reviewed by CalculatorX electrical review
- Definition
- Affine conversion: K = °C + 273.15 and °C = K − 273.15. Kelvin is absolute and must be ≥ 0.
- What it calculates
- Celsius ↔ Kelvin conversion.
- Inputs
- mode c-k|k-c
- value
- Outputs
- K or °C number
- Formula
K=C+273.15- Assumptions
- ITS-90 offset 273.15
- Units
- °C, K
- Boundary conditions
- K<0 → VALUE_OUT_OF_RANGE
- missing value → MISSING_REQUIRED_INPUT
- Example
- 25 °C → 298.15 K
- Validation cases
1 published on this page · 6/6 tests · Production surface contract 4/4 · View evidence
- c-k value=25 → 298.15
- Sources
- SI temperature units — Kelvin / Celsius relationSupports: K = °C + 273.15
- NIST / SI temperature — kelvin and CelsiusSupports: T/K = t/°C + 273.15
- SI temperature units — Kelvin / Celsius relation
- Last reviewed
- 2026-08-09
- Reviewed by
- CalculatorX electrical review
- Calculation version
- 1.0.0
Background
Interpretation and common distinctions.
Convert Celsius ↔ Kelvin with Trusted Template guards.
Supported and not supported
Supported — Bidirectional °C↔K · API units.temperature.celsius_kelvin
Not supported — Fahrenheit / Rankine (use temperature converters)
Agent / API notes
Capability id: units.temperature.celsius_kelvin · tool id: celsius-kelvin · pin 1.0.0.
Related tools
Other calculators in this family: Ideal Gas, Heat Transfer .
Frequently asked questions
Key distinctions behind the calculation.
Can Kelvin be negative?
No. The API returns VALUE_OUT_OF_RANGE for K < 0 or °C < −273.15.