# Rankine to Rømer (°R to °Rø) Source: https://www.unitconvertercalculator.com/temperature/rankine-to-romer/ To convert Rankine to Romer, use the formula: Ro = (R - 491.67) x 7/24 + 7.5. The Rankine scale is the absolute Fahrenheit scale used in US thermodynamic engineering, while the Romer scale is the early Danish scale that influenced Fahrenheit. Water freezes at 491.67 degrees R (7.5 Ro) and boils at 671.67 degrees R (60 Ro). ## Formula °R via Kelvin to °Rø ## Conversion Table | Rankine (°R) | Rømer (°Rø) | |---|---| | 0 °R | -135.90375 °Rø | | 100 °R | -106.73708333333 °Rø | | 200 °R | -77.570416666667 °Rø | | 300 °R | -48.403749999998 °Rø | | 400 °R | -19.237083333334 °Rø | | 459 °R | -2.02875 °Rø | | 491.67 °R | 7.5 °Rø | | 500 °R | 9.9295833333345 °Rø | | 530 °R | 18.679583333331 °Rø | | 559 °R | 27.137916666669 °Rø | | 600 °R | 39.096249999998 °Rø | | 671.67 °R | 60 °Rø | | 700 °R | 68.262916666667 °Rø | | 800 °R | 97.429583333331 °Rø | | 1000 °R | 155.76291666667 °Rø | ## Units ### Rankine (°R) An absolute temperature scale using Fahrenheit-sized degrees. 0 °R equals absolute zero. Used in some US engineering applications, especially thermodynamics. ### Rømer (°Rø) A temperature scale proposed by Ole Christensen Rømer in 1701. Water freezes at 7.5 °Rø and boils at 60 °Rø. It influenced Fahrenheit's scale development. ## Background The Rankine scale was created by William Rankine, 1859, used in American aerospace and chemical engineering. The Romer scale was created by Ole Romer, Danish astronomer, around 1701, influenced Fahrenheit. Converting between them bridges different eras and different measurement philosophies in the history of thermometry. ## Good to Know The history of temperature measurement is the history of scientific collaboration and competition across borders. The Rankine scale (used in American aerospace and chemical engineering) and the Romer scale (influenced Fahrenheit) represent different national contributions to solving the same fundamental problem: how to assign numbers to the sensation of hot and cold. ## FAQ ### How do you convert Rankine to Romer? Use the formula Ro = (R - 491.67) x 7/24 + 7.5. At the freezing point of water: 491.67 R = 7.5 Ro. At the boiling point: 671.67 R = 60 Ro. ### When would you need to convert Rankine to Romer? This conversion is needed when interpreting historical scientific records, comparing temperature data across different measurement traditions, or completing engineering calculations that mix temperature scales from different national standards. ### What are the key reference points for both scales? Water freezes at 491.67 R = 7.5 Ro. Water boils at 671.67 R = 60 Ro. These two fixed points anchor both scales and provide easy verification of any conversion calculation. ## Non-Frequently Asked Questions ### Is Rankine-to-Romer the most obscure temperature conversion possible? It is arguably the most obscure conversion between named temperature scales. Rankine is used by a small group of American engineers. Romer is used by essentially nobody. The intersection of people who need to convert between them is so small it might actually be empty. This conversion exists because conversion tables aim for completeness, not for anticipated demand. ### Would William Rankine have known about Romer's scale? Possibly. Rankine was a well-read Scottish engineer and physicist who would have encountered Romer's name in the history of thermometry. But he created the Rankine scale (1859) for American engineering purposes, not for historical comparison with a defunct Danish scale. Rankine wanted practical absolute temperatures; Romer was a historical footnote by then. ### If all seven temperature scales in this converter held an election, which would win? Celsius would win by landslide - used by roughly 95 percent of the world's population. Fahrenheit would come second with 330 million American voters. Kelvin would win the scientific community's endorsement. Rankine would carry a few engineering departments. Newton, Delisle, Reaumur, and Romer would each receive approximately zero votes, splitting the obsolescence demographic evenly. ## Related Articles - [Why We Measure: The Deepest Urge in Human Civilisation](https://www.unitconvertercalculator.com/blog/why-we-measure) - [The Map Is Not the Territory: Why Every Measurement Is Wrong](https://www.unitconvertercalculator.com/blog/the-map-is-not-the-territory) - [Zero: The Most Dangerous Number in Measurement](https://www.unitconvertercalculator.com/blog/zero-the-most-dangerous-number-in-measurement) - [The Speed of Everything: How We Measure From Glaciers to Light](https://www.unitconvertercalculator.com/blog/the-speed-of-everything) - [Why Your Recipe Is Lying to You: The Chaos of Cooking Measurements](https://www.unitconvertercalculator.com/blog/why-recipe-measurements-are-unreliable) - [When Measurements Go Wrong - Disasters, Blunders and Happy Accidents](https://www.unitconvertercalculator.com/blog/when-measurements-go-wrong) - [The Surprising Stories Behind Everyday Units of Measurement](https://www.unitconvertercalculator.com/blog/stories-behind-measurement-units) - [Metric vs. Imperial - The Complete Guide to the World's Two Measurement Systems](https://www.unitconvertercalculator.com/blog/metric-vs-imperial-complete-guide) - [Temperature Conversion Guide for Travel, Cooking & Weather](https://www.unitconvertercalculator.com/blog/temperature-conversion-guide) ## See Also - [Rømer to Rankine](https://www.unitconvertercalculator.com/temperature/romer-to-rankine/)