What is degree Celsius?

Degree Celsius is a temperature unit based on the freezing and boiling points of water at standard atmospheric pressure. It is the most widely used scale for weather forecasting, cooking, and everyday temperature reporting worldwide.

Real-world uses

Celsius is used for everyday temperature in most of the world—weather forecasts, cooking temperatures, body temperature (37°C normal), and industrial process controls. Scientific publications outside the US typically report temperatures in °C.

History

Proposed by Swedish astronomer Anders Celsius in 1742, originally with 0° as the boiling point and 100° as freezing. Carl Linnaeus inverted the scale to its modern form shortly after. It was renamed from "centigrade" to "Celsius" in 1948 by the CGPM.

Common mistakes

Assuming Celsius and Fahrenheit scales cross at intuitive points. They intersect at −40°, not at 0° or 100°. Also, confusing a "degree Celsius change" with a "degree Fahrenheit change"—a 1°C change equals a 1.8°F change.

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.

When is this conversion used?

Converting between degree Celsius and degree Rankine is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region. 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 Celsius = 493.47 degree Rankine

1 degree Rankine = 0.55555556 kelvin

How to convert degree Celsius to degree Rankine

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 Celsius to degree Rankine

degree Celsiusdegree Rankine
0.000000e+00491.67
10509.67
20527.67
25536.67
37558.27
50581.67
100671.67
200851.67
5001,391.67

Common values

degree Celsiusdegree Rankine
Water freezes0.000000e+00 degree Celsius0.000000e+00 degree Rankine
Room temperature21 degree Celsius21 degree Rankine
Human body37 degree Celsius37 degree Rankine
Oven baking180 degree Celsius180 degree Rankine
Water boils100 degree Celsius100 degree Rankine