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Equivalent temperature
Accurate temperature conversion tool for °C to °R and °R to °C
Convert Celsius to Rankine instantly with precise calculations. Includes bidirectional conversion, formula breakdown, and full reference table for 2026.
Professional temperature conversion for thermodynamics, engineering, science, and industrial use
Convert Celsius (°C) to Rankine (°R) using the exact formula: °R = (°C + 273.15) × 9/5. Our tool delivers accurate results for any temperature — from absolute zero through to extreme industrial and astrophysical temperatures.
Switch seamlessly between Celsius to Rankine and Rankine to Celsius conversion modes. Get instant results alongside related temperature scales including Kelvin, Fahrenheit, and Réaumur — all from a single input value.
Essential for thermodynamic calculations, aerospace engineering, chemical process design, refrigeration engineering, and any scientific discipline where absolute temperature scales are required alongside the Celsius system used in everyday measurements.
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The Celsius scale (°C) is the world's most widely used temperature scale for everyday and scientific purposes, with water freezing at 0°C and boiling at 100°C at standard atmospheric pressure. The Rankine scale (°R or °Ra) is an absolute thermodynamic temperature scale based on the Fahrenheit degree interval, proposed by Scottish engineer William John Macquorn Rankine in 1859. Its zero point — absolute zero — is the same as Kelvin's (0 K = 0°R), but degrees are sized like Fahrenheit rather than Celsius, making 1°R = 5/9 K.
The Rankine scale is used primarily in engineering thermodynamics, particularly in the United States aerospace and chemical industries, where equations involving absolute temperature are required but engineers prefer the Fahrenheit degree interval. Converting from Celsius to Rankine requires first converting to Kelvin (add 273.15), then multiplying by 9/5 to account for the Fahrenheit-sized degree interval.
Rankine values are always positive and always larger than Celsius — the zero points are offset by 491.67°R (= 273.15 × 1.8).
Use this quick reference table for common Celsius to Rankine conversions. Values cover the full range from absolute zero through everyday temperatures to extreme industrial and scientific applications.
| Celsius (°C) | Rankine (°R) | Kelvin (K) | Fahrenheit (°F) | Description |
|---|---|---|---|---|
| −273.15°C | 0.00°R | 0.00 K | −459.67°F | Absolute Zero |
| −200°C | 131.67°R | 73.15 K | −328°F | Cryogenic range |
| −100°C | 311.67°R | 173.15 K | −148°F | Dry ice temp. |
| −40°C | 419.67°R | 233.15 K | −40°F | °C = °F crossover |
| −20°C | 455.67°R | 253.15 K | −4°F | Cold winter |
| 0°C | 491.67°R | 273.15 K | 32°F | Water freezes |
| 20°C | 527.67°R | 293.15 K | 68°F | Room temperature |
| 37°C | 558.27°R | 310.15 K | 98.6°F | Human body temp. |
| 100°C | 671.67°R | 373.15 K | 212°F | Water boils |
| 200°C | 851.67°R | 473.15 K | 392°F | Industrial oven |
| 500°C | 1,391.67°R | 773.15 K | 932°F | Furnace temp. |
| 1,000°C | 2,291.67°R | 1,273.15 K | 1,832°F | Molten iron |
| 5,000°C | 9,491.67°R | 5,273.15 K | 9,032°F | Sun surface approx. |
Converting Celsius to Rankine is a two-step process. You must first shift from the Celsius scale to an absolute scale (Kelvin), then scale by 9/5 to account for the Fahrenheit-sized degree interval used by Rankine. Here is the step-by-step guide for both directions:
Remember that 0°C = 491.67°R. For every 1°C increase, Rankine increases by 1.8°R (the same ratio as Fahrenheit). So if you know a temperature in Celsius, add 273.15 and multiply by 1.8 — or just remember that room temperature (20°C) ≈ 527.67°R as your mental anchor point.
The Rankine scale is the absolute temperature scale of choice in US engineering, particularly in thermodynamic calculations involving the ideal gas law, entropy, and enthalpy when working in imperial units. Equations like PV = nRT require temperature to be expressed in absolute terms — and for engineers using psi, BTU, and pounds, Rankine is the natural absolute scale, just as Kelvin serves SI-unit systems. Converting from Celsius — the scale used for most experimental measurements and international data — to Rankine is therefore a routine requirement in US engineering practice.
US aerospace engineering standards, including many NASA technical documents, use Rankine as the absolute temperature scale. Combustion temperatures, heat shield ratings, and thermodynamic cycle analyses in American aerospace all require converting metric Celsius values from international data into Rankine for calculations in imperial units.
Process engineers in the US chemical industry use Rankine in thermodynamic equations involving enthalpy, entropy, and the ideal gas law when working in BTU and pound-force units. Converting experimental temperature data from Celsius to Rankine is a standard step in heat exchanger design and reactor modelling.
Refrigeration cycle calculations — including Coefficient of Performance (COP) and compressor work — use absolute temperature scales. US refrigeration engineers working with imperial units use Rankine for these calculations, requiring conversion from the Celsius values reported on thermometers and datasheets.
Academic and industrial thermodynamics research published in US journals often presents temperature data in both Celsius and Rankine. Researchers reviewing international literature in Celsius must convert to Rankine to apply findings to American engineering formulas and to compare results with US-based experimental datasets.
Steam power plant engineers using imperial unit systems — including many older US facilities — specify boiler temperatures, turbine inlet conditions, and condenser temperatures in Rankine. Converting from the Celsius readings of modern digital sensors requires accurate °C to °R conversion for legacy system compatibility.
While most modern astrophysics uses Kelvin, some American textbooks and historical literature reference stellar temperatures and cosmic background radiation values in Rankine. Students and researchers working across these sources need reliable Celsius-to-Rankine conversion to reconcile data from different publications.
Here is a full reference showing how all major temperature scales relate to each other — an essential quick-reference for engineers, scientists, and students working across Celsius, Rankine, Kelvin, and Fahrenheit systems.
| Scale | Absolute Zero | Water Freezes | Body Temp. | Water Boils |
|---|---|---|---|---|
| Celsius (°C) | −273.15°C | 0°C | 37°C | 100°C |
| Rankine (°R) | 0°R | 491.67°R | 558.27°R | 671.67°R |
| Kelvin (K) | 0 K | 273.15 K | 310.15 K | 373.15 K |
| Fahrenheit (°F) | −459.67°F | 32°F | 98.6°F | 212°F |
| Réaumur (°Ré) | −218.52°Ré | 0°Ré | 29.6°Ré | 80°Ré |
| Delisle (°De) | 559.73°De | 150°De | 94.5°De | 0°De |
The National Institute of Standards and Technology provides authoritative reference data for temperature scales, thermodynamic properties, and unit conversion factors used in engineering and scientific research worldwide.
Visit NIST →The International Bureau of Weights and Measures defines the Kelvin as the SI base unit of thermodynamic temperature. Their documentation covers the relationship between all temperature scales including Celsius, Kelvin, and derived absolute scales.
Visit BIPM →Explore our full library of free metric and imperial unit converters covering temperature, length, area, volume, pressure, energy, time, flow rate, and more. All tools are mobile-friendly and completely free to use.
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