Convert Rankine to Kelvin
Kelvin = Rankine × 0.5555556. Type any temperature below to convert rankine to kelvin both ways — it runs entirely in your browser.
Rankine to Kelvin formula
Temperature scales have different zero points, so the conversion is a multiply-and-add, not a single ratio:
Kelvin = Rankine × 0.5555556
To go the other way, Rankine = Kelvin × 1.8.
Worked example
Convert 540 °R to kelvin:
= 540 × 0.5555556 = 300 K.
Common temperatures in Rankine and Kelvin
| Reference point | Rankine (°R) | Kelvin (K) |
|---|---|---|
| Absolute zero | 0 | 0 |
| Freezing point of water | 491.67 | 273.15 |
| Refrigerator | 498.87 | 277.15 |
| Room temperature | 529.47 | 294.15 |
| Normal human body temperature | 558.27 | 310.15 |
| A hot summer day | 572.67 | 318.15 |
| Boiling point of water (sea level) | 671.67 | 373.15 |
About the Rankine and Kelvin scales
Rankine: The Rankine scale starts at absolute zero like Kelvin but uses the Fahrenheit-sized degree (0 °R = −459.67 °F). It appears in some US engineering and thermodynamics work.
Kelvin: The kelvin is the SI base unit of temperature. It starts at absolute zero (0 K = −273.15 °C) and uses the same degree size as Celsius, so it is written without a degree sign.
Sources
- NIST Special Publication 811 — Guide for the Use of the SI — publishes the defining relations between the temperature scales. Unlike every other conversion on this site these are affine, not a single multiplying factor: t/°C = (t/°F − 32)/1.8 and T/K = (T/°R)/1.8 are exact by definition, so the figures here are exact rather than rounded — the scales simply have different zero points as well as different degree sizes.
- BIPM — The International System of Units (SI Brochure) — the defining document for the SI, published by the International Bureau of Weights and Measures. It fixes the base unit that this conversion resolves to, which is why the factor here can be exact rather than approximate.
Frequently asked questions
- What is 540 °R in Kelvin?
- 540 °R = 300 K.
- How do I convert Rankine to Kelvin?
- Use kelvin = rankine × 0.5555556. For example, 540 °R → 300 K.
- How do I convert Kelvin back to Rankine?
- Reverse it: rankine = kelvin × 1.8.
- Is converting Rankine to Kelvin just multiplication?
- Yes — Rankine and Kelvin share the same zero (absolute zero), so kelvin = rankine × 0.5555556 with no constant added.