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 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?

Converting between degree Celsius and degree Fahrenheit 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 = 33.8 degree Fahrenheit

1 degree Fahrenheit = 0.55555556 kelvin

How to convert degree Celsius 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 Celsius to degree Fahrenheit

degree Celsius	degree Fahrenheit
0.000000e+00	32
10	50
20	68
25	77
37	98.6
50	122
100	212
200	392
500	932

Common values

	degree Celsius	degree Fahrenheit
Water freezes	0.000000e+00 degree Celsius	0.000000e+00 degree Fahrenheit
Room temperature	21 degree Celsius	21 degree Fahrenheit
Human body	37 degree Celsius	37 degree Fahrenheit
Oven baking	180 degree Celsius	180 degree Fahrenheit
Water boils	100 degree Celsius	100 degree Fahrenheit

Available Temperature units

More degree Celsius conversions

Assumption: formula-based scales using Kelvin as reference.