Length · Unit Converter

Convert A.u. of Length to Centimeter

Convert a.u. of length to centimeters instantly. 1 a.u. of length = 5.291772e-9 centimeter — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Centimeter to A.u. of Length converter for the reverse conversion.

Written by Sunith Babu L, Ph.D., Lead Engineer Reviewed by Girish V Kulkarni Ph.D.
Length category 2 min read Published Last reviewed Updated

Units explained

Astronomical

A.u. of Length

What is a a.u. of length?

The atomic unit of length (a.u.) is equal to the Bohr radius — approximately 5.292×10⁻¹¹ m. Despite the abbreviation matching 'astronomical unit', this is a different unit used in atomic and molecular physics.

Origin of the a.u. of length

The atomic unit system was developed in the 1950s for quantum-chemistry calculations. The a.u. of length is defined as the Bohr radius (a₀), the most probable distance between the proton and electron in a hydrogen atom in its ground state.

Where it is used

The atomic unit of length is used throughout quantum chemistry, electronic-structure theory, and computational physics. Most quantum-mechanical equations simplify when expressed in atomic units rather than SI units.

When and where it was developed

Atomic unit system developed by Hartree in the 1920s; value fixed via CODATA 2018 determination of fundamental physical constants.

Metric / SI

Centimeter

What is a 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.

Origin of the centimeter

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.

Where it is used

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.

When and where it was developed

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.

A.u. of Length to Centimeter conversion formula

The relationship between a.u. of length and centimeters:

1 a.u. = 5.291772e-9 cm
1 cm = 1.889726e+8 a.u.

To convert a.u. of length to centimeters, multiply the value in a.u. of length by 5.291772e-9. To reverse, multiply centimeters by 1.889726e+8.

How to use this converter

Type a value into the calculator. The result in centimeters updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Centimeter to A.u. of Length converter for the reverse direction.

Step-by-step: convert a.u. of length to centimeters

  1. Write down the value in a.u. of length (a.u.).
  2. Multiply that value by the factor 5.291772e-9.
  3. The product is the equivalent value in centimeters (cm).
  4. To reverse, multiply the centimeter value by 1.889726e+8.

Worked examples

Example 1 — Convert 1 a.u. to cm:
1 × 5.291772e-9 = 5.291772e-9 cm

Example 2 — Convert 100 a.u. to cm:
100 × 5.291772e-9 = 5.291772e-7 cm

Real-world example — From wavelengths to millimeter-scale objects

A value of one million a.u. of length sounds vast at the atomic scale but converts to a small everyday quantity in centimeters — useful when relating optical-wavelength specifications to physical mounting hardware.

1000000 a.u. × 5.291772e-9 = 0.0052917721 cm

Real-world example — Sub-micron to millimeter

500,000 a.u. of length converts to a small everyday quantity in centimeters — useful when relating optical-wavelength specifications to physical mounting hardware.

500000 a.u. × 5.291772e-9 = 0.0026458861 cm

A.u. of Length to Centimeter conversion table

Standard reference values for converting a.u. of length to centimeters:

A.u. of Length [a.u.]Centimeter [cm]
0.015.291772e-11
0.15.291772e-10
15.291772e-9
21.058354e-8
31.587532e-8
42.116709e-8
52.645886e-8
105.291772e-8
201.058354e-7
301.587532e-7
402.116709e-7
502.645886e-7
1005.291772e-7
5002.645886e-6
10005.291772e-6

Frequently asked questions

How many centimeters is 1 a.u. of length?
1 a.u. of length equals 5.291772e-9 centimeter.
How do I convert a.u. of length to centimeters?
Multiply the value in a.u. of length by 5.291772e-9 to get centimeters.
How do I convert centimeters back to a.u. of length?
Multiply the value in centimeters by 1.889726e+8, or use the Centimeter to A.u. of Length converter.
How many centimeters is 100 a.u. of length?
100 a.u. of length equals 5.291772e-7 centimeters, because 100 × 5.291772e-9 = 5.291772e-7.

Convert A.u. of Length to other length units

Show all A.u. of Length conversions

Sources & references

Conversion factor (1 a.u. = 5.291772e-9 cm) verified against the following authoritative sources:

Results are provided for general reference. Verify critical measurements against an authoritative standard.