Convert Femtometer to Centimeter
Convert femtometers to centimeters instantly. 1 femtometer = 1e-13 centimeter — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Centimeter to Femtometer converter for the reverse conversion.
Units explained
Femtometer
A femtometer is a metric unit of length equal to one quadrillionth of a meter (1×10⁻¹⁵ m). It is the standard unit for measuring sub-atomic dimensions, particularly the size of atomic nuclei. The femtometer is also known historically as the fermi.
The femtometer was defined using the SI prefix femto- (from Danish femten, meaning fifteen), adopted by the CGPM in 1964 to denote one quadrillionth. The synonymous name fermi was named after Italian physicist Enrico Fermi.
Femtometers are used to express the size of atomic nuclei (typically 1–10 fm in diameter), the range of strong nuclear forces, and characteristic dimensions in particle physics. The proton charge radius is approximately 0.84 fm.
SI prefix femto- adopted in 1964; the unit became standard in nuclear physics through the late 20th century. The name fermi (after Enrico Fermi) was used informally from the 1950s but officially superseded by femtometer.
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.
Femtometer to Centimeter conversion formula
The relationship between femtometers and centimeters:
To convert femtometers to centimeters, multiply the value in femtometers by 1e-13. To reverse, multiply centimeters by 1e+13.
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 Femtometer converter for the reverse direction.
Step-by-step: convert femtometers to centimeters
- Write down the value in femtometers (fm).
- Multiply that value by the factor 1e-13.
- The product is the equivalent value in centimeters (cm).
- To reverse, multiply the centimeter value by 1e+13.
Worked examples
Example 1 — Convert 1 fm to cm:
1 × 1e-13 = 1e-13 cm
Example 2 — Convert 100 fm to cm:
100 × 1e-13 = 1e-11 cm
Real-world example — Sub-micron to millimeter
500,000 femtometers converts to a small everyday quantity in centimeters — useful when relating optical-wavelength specifications to physical mounting hardware.
500000 fm × 1e-13 = 5e-8 cm
Real-world example — From wavelengths to millimeter-scale objects
A value of one million femtometers 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 fm × 1e-13 = 1e-7 cm
Femtometer to Centimeter conversion table
Standard reference values for converting femtometers to centimeters:
| Femtometer [fm] | Centimeter [cm] |
|---|---|
| 0.01 | 1e-15 |
| 0.1 | 1e-14 |
| 1 | 1e-13 |
| 2 | 2e-13 |
| 3 | 3e-13 |
| 4 | 4e-13 |
| 5 | 5e-13 |
| 10 | 1e-12 |
| 20 | 2e-12 |
| 30 | 3e-12 |
| 40 | 4e-12 |
| 50 | 5e-12 |
| 100 | 1e-11 |
| 500 | 5e-11 |
| 1000 | 1e-10 |
Frequently asked questions
How many centimeters is 1 femtometer?
How do I convert femtometers to centimeters?
How do I convert centimeters back to femtometers?
How many centimeters is 100 femtometers?
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Sources & references
Conversion factor (1 fm = 1e-13 cm) 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.