What is degree Rankine?

Degree Rankine is an absolute temperature scale based on Fahrenheit-sized degrees, where zero is absolute zero. It is used in engineering thermodynamics in the United States, particularly in aerospace and mechanical engineering calculations.

Real-world uses

The Rankine scale is used in some American engineering fields, particularly thermodynamics, combustion engineering, and heat transfer calculations where an absolute temperature in Fahrenheit-sized degrees is needed. It appears in US engineering textbooks and ASHRAE standards.

History

Named after Scottish-Irish engineer William John Macquorn Rankine, who proposed it in 1859. It serves as the Fahrenheit-scale analogue of kelvin. While kelvin uses Celsius-sized degrees from absolute zero, Rankine uses Fahrenheit-sized degrees from absolute zero.

Common mistakes

Confusing Rankine with Fahrenheit—Rankine starts at absolute zero (0°R = −459.67°F), not at 0°F. Also, forgetting that the conversion from Fahrenheit is simply °R = °F + 459.67.

What is degree Fahrenheit?

Degree Fahrenheit is a temperature unit primarily used in the United States for weather reports, cooking temperatures, and household settings. Water freezes at 32 °F and boils at 212 °F on this scale.

Real-world uses

Fahrenheit is the standard temperature unit in the United States for weather reports, oven settings, and body temperature (98.6°F normal). Some Caribbean nations and Liberia also use it. Pool and spa temperatures in the US are set in °F.

History

Daniel Gabriel Fahrenheit, a Polish-Dutch physicist, proposed this scale in 1724. He set 0°F as the temperature of a brine solution, 32°F as the freezing point of water, and 96°F as approximate body temperature. The scale was later adjusted slightly.

Common mistakes

Using the formula °F = °C × 2 + 30 as an exact conversion—it is only a rough estimate. The correct formula is °F = °C × 9/5 + 32. Also, assuming 0°F is absolute zero; it is actually about −17.8°C.

When is this conversion used?

This is the most common temperature conversion worldwide, needed for weather reports, cooking temperatures, and medical readings. Most of the world uses Celsius while the US primarily uses Fahrenheit.

Worked examples

1 degree Rankine = -458.67 degree Fahrenheit

1 degree Fahrenheit = 0.55555556 kelvin

How to convert degree Rankine to degree Fahrenheit

Temperature conversion uses a formula rather than a constant multiplier. The interactive converter above handles all calculations automatically.

Measurement standards

The kelvin is the SI base unit of thermodynamic temperature, defined by fixing the Boltzmann constant to exactly 1.380649 × 10⁻²³ joules per kelvin. This definition, adopted in 2019, decoupled the kelvin from the triple point of water.

Did you know?

The coldest temperature ever recorded on Earth was −89.2 °C (−128.6 °F) at the Soviet Vostok Station in Antarctica on 21 July 1983. In laboratories, scientists have cooled atoms to within billionths of a kelvin above absolute zero.

Quick reference: degree Rankine to degree Fahrenheit

Common values

Available Temperature units

• degree Celsius conversions
• degree Fahrenheit conversions
• kelvin conversions
• degree Rankine conversions
• degree Réaumur conversions

More degree Rankine conversions

• Convert degree Rankine to degree Celsius
• Convert degree Rankine to degree Fahrenheit
• Convert degree Rankine to kelvin
• Convert degree Rankine to degree Réaumur

Assumption: formula-based scales using Kelvin as reference.