Convert Centimeter to Astronomical Unit
Convert centimeters to astronomical units instantly. 1 centimeter = 6.684587e-14 astronomical unit — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Astronomical Unit to Centimeter converter for the reverse conversion.
Units explained
Centimeter
A centimeter is a metric unit of length equal to one hundredth of a meter (1/100 m). It is one of the most commonly used SI sub-units in daily life, especially for measuring small objects, body dimensions, paper sizes, and short distances.
The centimeter emerged from the French metric system established by the French Academy of Sciences in 1793. The metric system introduced decimal-based prefixes (milli-, centi-, deci-, deca-, hecto-, kilo-) to create proportional sub-units of the meter.
Centimeters are the standard unit for everyday measurement in nearly every country outside the United States. They are used for body height, clothing sizes, rainfall, paper formats (A4 is 21 × 29.7 cm), screen dimensions, and most consumer product specifications.
Developed in France during the late 18th century as part of the metric system designed by the French Academy of Sciences. Formally adopted in France in 1795 and ratified internationally through the Metre Convention signed in Paris in 1875.
Astronomical Unit
The astronomical unit (AU) is a unit of length equal to exactly 149,597,870,700 meters, approximately the average distance from Earth to the Sun. It is the fundamental unit for distance within the solar system.
The AU was originally defined as the semi-major axis of Earth's orbit. In 2012, IAU Resolution B2 redefined the AU as exactly 149,597,870,700 meters, severing its dependence on the actual fluctuating Earth–Sun distance.
AUs are used to express distances within the solar system (Mars: 1.5 AU, Pluto: ~40 AU at perihelion), exoplanet orbital radii, and other planetary-scale distances. Standard in planetary science and astronomy.
Original definition tied to Earth's orbit (Newton, 17th century); fixed at exactly 149,597,870,700 m by IAU Resolution B2 in 2012.
Centimeter to Astronomical Unit conversion formula
The relationship between centimeters and astronomical units:
To convert centimeters to astronomical units, multiply the value in centimeters by 6.684587e-14. To reverse, multiply astronomical units by 1.495979e+13.
How to use this converter
Type a value into the calculator. The result in astronomical units updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Astronomical Unit to Centimeter converter for the reverse direction.
Step-by-step: convert centimeters to astronomical units
- Write down the value in centimeters (cm).
- Multiply that value by the factor 6.684587e-14.
- The product is the equivalent value in astronomical units (AU).
- To reverse, multiply the astronomical unit value by 1.495979e+13.
Worked examples
Example 1 — Convert 1 cm to AU:
1 × 6.684587e-14 = 6.684587e-14 AU
Example 2 — Convert 100 cm to AU:
100 × 6.684587e-14 = 6.684587e-12 AU
Real-world example — Hardware-scale dimensions
A 10-centimeter fastener or component is about as long as a thumbnail. Mechanics and DIY enthusiasts convert between centimeters and astronomical units daily when mixing metric and imperial tools.
10 cm × 6.684587e-14 = 6.684587e-13 AU
Real-world example — Postcard and small-object dimensions
A postcard is about 5 centimeters wide. Converting to astronomical units is essential for international postal addressing forms that ask for dimensions in different units across countries.
5 cm × 6.684587e-14 = 3.342294e-13 AU
Real-world example — Ruler-scale measurements
A 30-centimeter school ruler converts cleanly to astronomical units — useful when buying a desk accessory from a retailer whose product specs use a different unit.
30 cm × 6.684587e-14 = 2.005376e-12 AU
Centimeter to Astronomical Unit conversion table
Standard reference values for converting centimeters to astronomical units:
| Centimeter [cm] | Astronomical Unit [AU] |
|---|---|
| 0.01 | 6.684587e-16 |
| 0.1 | 6.684587e-15 |
| 1 | 6.684587e-14 |
| 2 | 1.336917e-13 |
| 3 | 2.005376e-13 |
| 4 | 2.673835e-13 |
| 5 | 3.342294e-13 |
| 10 | 6.684587e-13 |
| 20 | 1.336917e-12 |
| 30 | 2.005376e-12 |
| 40 | 2.673835e-12 |
| 50 | 3.342294e-12 |
| 100 | 6.684587e-12 |
| 500 | 3.342294e-11 |
| 1000 | 6.684587e-11 |
Frequently asked questions
How many astronomical units is 1 centimeter?
How do I convert centimeters to astronomical units?
How do I convert astronomical units back to centimeters?
How many astronomical units is 100 centimeters?
Popular length unit conversions
Convert Centimeter to other length units
Show all Centimeter conversions
Metric / SI (17 units)
Imperial / US Customary (27 units)
Nautical (1 units)
Astronomical (9 units)
Atomic / Physics (6 units)
Typographic (3 units)
Sources & references
Conversion factor (1 cm = 6.684587e-14 AU) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.