Convert Centimeter to Exameter
Convert centimeters to exameters instantly. 1 centimeter = 1e-20 exameter — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Exameter 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.
Exameter
An exameter is a metric unit of length equal to one quintillion meters (1×10¹⁸ m). It is among the largest defined SI prefix units of length and appears almost exclusively in astrophysical contexts.
The exameter uses the SI prefix exa- (from Greek hex, six, related to the exponent's powers-of-thousand grouping), adopted by the CGPM in 1975 to denote 10¹⁸.
Exameters could be used to express galactic-scale distances. One kiloparsec is approximately 30.9 Em. Astronomy generally uses parsecs, kiloparsecs, and megaparsecs instead.
SI prefix exa- adopted in 1975; the exameter has very limited practical use because galactic-scale astronomy has its own well-established unit system.
Centimeter to Exameter conversion formula
The relationship between centimeters and exameters:
To convert centimeters to exameters, multiply the value in centimeters by 1e-20. To reverse, multiply exameters by 1e+20.
How to use this converter
Type a value into the calculator. The result in exameters updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Exameter to Centimeter converter for the reverse direction.
Step-by-step: convert centimeters to exameters
- Write down the value in centimeters (cm).
- Multiply that value by the factor 1e-20.
- The product is the equivalent value in exameters (Em).
- To reverse, multiply the exameter value by 1e+20.
Worked examples
Example 1 — Convert 1 cm to Em:
1 × 1e-20 = 1e-20 Em
Example 2 — Convert 100 cm to Em:
100 × 1e-20 = 1e-18 Em
Real-world example — Postcard and small-object dimensions
A postcard is about 5 centimeters wide. Converting to exameters is essential for international postal addressing forms that ask for dimensions in different units across countries.
5 cm × 1e-20 = 5e-20 Em
Real-world example — Ruler-scale measurements
A 30-centimeter school ruler converts cleanly to exameters — useful when buying a desk accessory from a retailer whose product specs use a different unit.
30 cm × 1e-20 = 3e-19 Em
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 exameters daily when mixing metric and imperial tools.
10 cm × 1e-20 = 1e-19 Em
Centimeter to Exameter conversion table
Standard reference values for converting centimeters to exameters:
| Centimeter [cm] | Exameter [Em] |
|---|---|
| 0.01 | 1e-22 |
| 0.1 | 1e-21 |
| 1 | 1e-20 |
| 2 | 2e-20 |
| 3 | 3e-20 |
| 4 | 4e-20 |
| 5 | 5e-20 |
| 10 | 1e-19 |
| 20 | 2e-19 |
| 30 | 3e-19 |
| 40 | 4e-19 |
| 50 | 5e-19 |
| 100 | 1e-18 |
| 500 | 5e-18 |
| 1000 | 1e-17 |
Frequently asked questions
How many exameters is 1 centimeter?
How do I convert centimeters to exameters?
How do I convert exameters back to centimeters?
How many exameters is 100 centimeters?
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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 = 1e-20 Em) 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.