🌡️ K to °R — Kelvin to Rankine Converter

Switching between Kelvin and Rankine shows up constantly in cooking, weather, lab work, HVAC, and manufacturing. Use this dedicated k-to-r tool for a clean, instant answer. Results update as you type; formulas and tips below explain how k relates to r in plain language. Common in cooking, weather, lab work, HVAC, and manufacturing.

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Formula °R = K × 9/5

All Kelvin conversions

Unit	Name	Value
°C	Celsius	-272.15
°F	Fahrenheit	-457.87
°R	Rankine	1.8

Related Temperature conversions

°C → °F °F → °C °C → K K → °C °F → K

⚡ How to Convert Kelvin to Rankine

Multiply by 9/5 (= 1.8). Formula: °R = K × 9/5. Example: 300 K × 9/5 = 540°R. Reverse: K = °R × 5/9.

Worked Examples

Example 1 — Thermodynamics — converting SI reference to US tables

298.15 K × 9/5 = 536.67°R

Standard thermodynamic tables in the US use Rankine. A chemist converting the IUPAC standard temperature (298.15 K) to Rankine (536.67°R) can look up entropy and enthalpy values in older American engineering references.

Example 2 — Aerospace — turbine inlet temperature

1600 K × 9/5 = 2880°R

A modern jet engine turbine inlet operates at ~1600 K. US aerospace engineers cross-referencing NASA legacy technical reports (in Rankine) convert to 2880°R to find matching historical efficiency data.

Example 3 — Cryogenics — liquid hydrogen boiling point

20.28 K × 9/5 = 36.5°R

Liquid hydrogen boils at 20.28 K. US aerospace propulsion engineers (SpaceX, NASA) using Rankine-based cryogenic tables convert to 36.5°R for propellant thermodynamic property lookups.

Example 4 — Process engineering — steam properties

500 K × 9/5 = 900°R

A process engineer calculating steam properties at 500 K converts to 900°R to use a Rankine-based steam table from an older American edition of Perry's Chemical Engineers' Handbook.

Kelvin to Rankine — Reference Table

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

Mental Math Tricks for K ↔ °R

Multiply by 1.8 — simple as that

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.

Reverse: divide by 1.8

°R ÷ 1.8 = K. 540°R ÷ 1.8 = 300 K.

Anchor: 300 K = 540°R

A round number anchor: 300 K (≈27°C) = 540°R. Scale proportionally from this point.

No offset needed

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.

Who Uses This Conversion?

Real professions and situations that need K to °R conversion

✈️

Aerospace Engineers Using Legacy NASA Data

NASA technical reports from the 1960s–1990s frequently use Rankine. Engineers working on systems derived from that era convert modern Kelvin values to Rankine when cross-referencing historical performance data.

🏭

US Chemical & Process Engineers

Legacy Aspen HYSYS configurations, older Perry's Handbook editions and some ASME steam tables use Rankine. Engineers inputting scientific Kelvin data into these tools convert to Rankine at the boundary between scientific and engineering workflows.

🎓

US Engineering Thermodynamics Students

American thermo textbooks present problems in both Rankine and Kelvin. Students converting Kelvin scientific data to Rankine for use in US-format worked examples and homework sets need this conversion regularly.

🔥

Combustion & Propulsion Engineers

Rocket propulsion and gas turbine combustion calculations span both Kelvin (scientific literature) and Rankine (US engineering practice). Engineers in this field convert between them multiple times per project.

📐

Standards Bodies & Technical Writers

Engineers writing ASME or API standards documents that reference SI Kelvin values must convert to Rankine for the US customary unit versions of those documents.

🌡️

Thermodynamics Researchers

Comparing thermodynamic property databases — some in SI (Kelvin), some in US customary (Rankine) — requires this conversion to verify consistency of reference data across different sources.

All Kelvin Conversions

Why this Kelvin to Rankine page is different

Below, FAQs and examples stay locked to k → r so search engines and readers get pair-specific guidance—not a reused template with names swapped.

Pair-specific questions (k to r)

No — Kelvin (k) and Rankine (r) measure the same kind of quantity but on different scales. Always convert with the correct factor before plugging values into equations or specs.

The live converter shows high-precision results and you can copy what you need. For official documents, round Kelvin/Rankine values to the precision your standard or client requires.

After converting, sanity-check against a known landmark value on this page’s reference table (for example a round Kelvin amount). If your result is wildly off that pattern, recheck the input unit.

Frequently Asked Questions

Multiply by 9/5 (or 1.8): °R = K × 9/5. Example: 300 K × 9/5 = 540°R.

0 K equals 0°R — both scales start at absolute zero, making this the simplest absolute temperature conversion.

273.15 K equals 491.67°R — the freezing point of water.

373.15 K equals 671.67°R — the boiling point of water.

Because both scales start at the same zero point (absolute zero). They only differ in degree size — 1 K = 9/5°R = 1.8°R. There is no offset constant needed, unlike Celsius-Fahrenheit conversions.

298.15 K equals 536.67°R — the standard thermodynamic reference temperature (25°C).

When using US engineering thermodynamic tables, legacy American process simulation software, or ASME/ASTM standards documents that specify temperatures in Rankine, starting from SI (Kelvin) scientific data.

About Kelvin and Rankine

Kelvin (K)

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.

Rankine (°R)

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.