Convert Kelvin to Rankine. Used in US engineering thermodynamics and legacy aerospace calculations.
| Unit | Name | Value |
|---|---|---|
| °C | Celsius | -272.15 |
| °F | Fahrenheit | -457.87 |
| °R | Rankine | 1.8 |
Multiply by 9/5 (= 1.8). Formula: °R = K × 9/5. Example: 300 K × 9/5 = 540°R. Reverse: K = °R × 5/9.
| Kelvin (K) | Rankine (°R) | Real-world context |
|---|---|---|
| 0 K | 0°R | Absolute zero — both scales start here |
| 77.15 K | 138.87°R | Liquid nitrogen boiling point |
| 273.15 K | 491.67°R | Water freezing point |
| 298.15 K | 536.67°R | Standard thermodynamic reference (25°C) |
| 310.15 K | 558.27°R | Human body temperature |
| 373.15 K | 671.67°R | Water boiling point |
| 1000 K | 1800°R | Industrial furnace range |
| 5778 K | 10400.4°R | Surface of the Sun |
K × 1.8 = °R. Both start at zero so there's no offset. 300 K × 1.8 = 540°R. This is one of the simplest temperature conversions.
°R ÷ 1.8 = K. 540°R ÷ 1.8 = 300 K.
A round number anchor: 300 K (≈27°C) = 540°R. Scale proportionally from this point.
Unlike Celsius↔Fahrenheit conversions, there is no "+32" or "−273" offset. Just multiply by 1.8. This is because both Kelvin and Rankine start at the same absolute zero point.
Real professions and situations that need K to °R conversion
The Kelvin (symbol: K) is the SI base unit of thermodynamic temperature, starting at absolute zero. Named after William Thomson (Lord Kelvin), it was adopted as an SI unit in 1954. Its degree intervals are identical to Celsius — 1 K = 1°C difference — but the scale begins 273.15 units below the Celsius zero.
Since 2019 the Kelvin is defined by fixing the Boltzmann constant at k = 1.380649×10⁻²³ J/K. Universal in scientific and international engineering, Kelvin has no degree symbol. It is the preferred absolute temperature scale worldwide outside of some legacy US engineering contexts.
The Rankine scale (symbol: °R) was proposed by William Rankine in 1859 as the Fahrenheit-based absolute temperature scale. Like Kelvin, it starts at absolute zero (0°R = 0 K), but uses Fahrenheit-sized degrees. The conversion is: °R = K × 9/5.
Rankine is primarily used in US engineering thermodynamics. While Kelvin has largely replaced Rankine even in US scientific practice, Rankine persists in legacy aerospace documentation, chemical engineering software and some ASTM/ASME standards. William Rankine was a prolific Scottish engineer who also made foundational contributions to thermodynamics, structural engineering and applied mechanics.
Common use: Kelvin-to-Rankine conversion is needed when working between SI scientific data (Kelvin) and US engineering legacy systems or documentation (Rankine). It is one of the simplest temperature conversions — just multiply by 9/5 — because both scales share the same zero point.