Convert Kelvin to Rankine – Temperature Converter
This converter converts a temperature given in kelvins (K) to degrees Rankine (°R). Kelvin and Rankine are absolute temperature scales; Kelvin is the SI base unit for temperature and Rankine is a Fahrenheit-based absolute scale commonly used in some engineering contexts.
The conversion is a fixed mathematical relationship and is exact: one degree Rankine equals 5/9 of a kelvin, or equivalently one kelvin equals 9/5 degrees Rankine. This page provides the formula, clear examples, and practical accuracy and traceability notes for instrument calibration and reporting.
Interactive Converter
Convert between kelvin and rankine with precision rounding.
Quick reference table
| Kelvin | Rankine |
|---|---|
| 1 K | 1.8 °R |
| 5 K | 9 °R |
| 10 K | 18 °R |
| 25 K | 45 °R |
| 50 K | 90 °R |
| 100 K | 180 °R |
Methodology
Conversion uses the exact ratio between the Kelvin and Rankine scales. Because both Kelvin and Rankine are absolute scales (zero at absolute zero), no offset term is required—only a scale factor.
For laboratory and engineering use, follow applicable metrology and calibration guidance to maintain traceability. Reference organizations include NIST for unit definitions and traceability, ISO for calibration and measurement standards, IEEE for instrumentation best practices, and OSHA for workplace temperature-related safety guidance.
When reporting converted values, consider the precision of the original measurement and the uncertainty from the measuring instrument or data source. Do not imply greater accuracy in the converted result than the original reading and its uncertainty allow.
Worked examples
300 K → 300 × 9/5 = 540 °R.
0 K → 0 × 9/5 = 0 °R (absolute zero).
273.15 K (0 °C) → 273.15 × 9/5 = 491.67 °R (reported based on input precision).
Key takeaways
Use °R = K × 9/5 for direct conversion from kelvin to degrees Rankine. The relationship is exact; however, converted results should respect the original measurement uncertainty and instrument calibration.
Consult and document applicable calibration and reporting standards such as NIST and ISO when using converted temperatures in regulated or safety-critical contexts.
Further resources
Expert Q&A
Is the conversion between kelvin and Rankine exact?
Yes. The conversion is an exact scaling: °R = K × 9/5. There is no additive offset because both scales share absolute zero as their zero point.
Do I need to consider calibration or uncertainty when converting?
Yes. Converting units does not change the measurement uncertainty or calibration status. Follow NIST and ISO guidance for calibration traceability and report converted values with uncertainty equal to the original measurement uncertainty propagated through the linear conversion.
Can I convert negative values?
Kelvin is an absolute scale and cannot be negative. If you have a negative temperature value, verify the unit (for example, degrees Celsius or Fahrenheit) before conversion. Rankine values are nonnegative when converting from valid Kelvin inputs.
How many decimal places should I report?
Report only as many decimal places as justified by the original measurement precision and uncertainty. Avoid implying greater accuracy by over-rounding converted results.
Where do these unit definitions come from?
Unit definitions and recommended practices are maintained by national and international bodies. See the cited authoritative sources for definitions, scales, and calibration guidance.
Sources & citations
- NIST Reference on Units and Constants — https://physics.nist.gov/cuu/Units/units.html
- International Organization for Standardization (ISO) — https://www.iso.org
- IEEE Standards Association — https://standards.ieee.org
- Occupational Safety and Health Administration (OSHA) — https://www.osha.gov