Convert Rankine to Kelvin - Temperature Converter

This converter transforms temperatures expressed in degrees Rankine (°R) to Kelvin (K). The conversion is a fixed mathematical scaling because both Rankine and Kelvin are absolute temperature scales; no offset is required.

Use this conversion for scientific calculations, engineering work, data logging, and unit standardization. While the mathematical conversion is exact, note that measured temperatures carry instrument uncertainty and may require calibration traceable to recognized standards.

Updated Nov 24, 2025QA PASS — golden 25 / edge 120Run golden-edge-2026-01-23

Governance

Record 4dd45234f8d8 • Reviewed by Fidamen Standards Committee

Interactive Converter

Convert between rankine and kelvin with precision rounding.

Rankine (°R)Kelvin (K)

Quick reference table

Rankine	Kelvin
1 °R	0.56 K
5 °R	2.78 K
10 °R	5.56 K
25 °R	13.89 K
50 °R	27.78 K
100 °R	55.56 K

Methodology

Rankine and Kelvin are absolute scales where 0 corresponds to absolute zero. A Rankine degree is defined as 1/°R = 5/9 of a Kelvin, so the conversion is a simple multiplicative factor.

This tool applies the exact scaling factor to the input value and then formats the result. For lab or regulatory uses, combine the numeric conversion with the measurement uncertainty and calibration certificate information from accredited laboratories or national metrology institutes.

Key takeaways

Use K = °R × 5/9 for direct conversion. The mathematical conversion is exact, but measurement uncertainty and calibration determine practical accuracy.

For regulated or precision work, ensure instruments are calibrated to traceable standards and report converted values with uncertainty and supporting calibration documentation.

Worked examples

Example 1: 0 °R → 0 K (absolute zero)

Example 2: 540 °R → 540 × 5/9 = 300 K

Example 3: 671.67 °R → 671.67 × 5/9 = 373.15 K (approx. 100 °C)

F.A.Q.

Is the Rankine to Kelvin conversion exact?

The mathematical relationship K = R × 5/9 is exact by definition of the scales. However, measured temperatures include instrument uncertainty, so report converted values together with the measurement uncertainty when precision matters.

Can I convert negative Rankine values?

Rankine is an absolute temperature scale where 0 °R corresponds to absolute zero; physically meaningful temperatures are non-negative. Negative inputs are mathematically convertible but represent non-physical values and should be treated cautiously.

How many decimal places should I keep?

Choose precision based on measurement uncertainty and downstream calculations. For display, 2–4 significant figures are common; for engineering or scientific calculations, keep extra digits and round only at the end.

Do I need to consider calibration or standards?

Yes. The conversion is numeric, but the accuracy of a converted reading depends on instrument calibration. Use instruments calibrated traceable to national standards (for example, NIST) and include calibration uncertainty in any compliance or reporting.

Are there regulatory limits tied to Kelvin values?

Regulatory agencies may set temperature-related exposure or process limits in different units. Convert values accurately for compliance checks, and consult the relevant regulatory guidance for how to report measurements and uncertainties.

Sources & citations

NIST Special Publication 811 - Guide for the Use of the International System of Units (SI) — https://www.nist.gov/pml/special-publication-811
ISO 80000 series — Quantities and units (general reference) — https://www.iso.org/iso-80000-1.html
OSHA heat stress information and workplace guidance — https://www.osha.gov/heat-exposure
IEEE Standards Association (standards catalog and guidance) — https://standards.ieee.org
NIST SP 330 — The International System of Units (SI) — https://www.nist.gov/pml/special-publication-330
BIPM SI Brochure (9th edition, 2019) — https://www.bipm.org/en/publications/si-brochure

Further resources

Related tools

Versioning & Change Control

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

Record ID: 4dd45234f8d8

What changed (latest)

v1.0.0 • 2025-11-24 • 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

Governance

Last updated: Nov 24, 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 • 2025-11-24 • 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: beebe3d14fd3