Length · Unit Converter

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.

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

Metric / SI

Femtometer

What is a 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.

Origin of the femtometer

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.

Where it is used

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.

When and where it was developed

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 The name fermi (after Enrico Fermi) was used informally from the 1950s but officially superseded by femtometer.

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.

Femtometer to Centimeter conversion formula

The relationship between femtometers and centimeters:

1 fm = 1e-13 cm
1 cm = 1e+13 fm

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

  1. Write down the value in femtometers (fm).
  2. Multiply that value by the factor 1e-13.
  3. The product is the equivalent value in centimeters (cm).
  4. 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]
0.011e-15
0.11e-14
11e-13
22e-13
33e-13
44e-13
55e-13
101e-12
202e-12
303e-12
404e-12
505e-12
1001e-11
5005e-11
10001e-10

Frequently asked questions

How many centimeters is 1 femtometer?
1 femtometer equals 1e-13 centimeter.
How do I convert femtometers to centimeters?
Multiply the value in femtometers by 1e-13 to get centimeters.
How do I convert centimeters back to femtometers?
Multiply the value in centimeters by 1e+13, or use the Centimeter to Femtometer converter.
How many centimeters is 100 femtometers?
100 femtometers equals 1e-11 centimeters, because 100 × 1e-13 = 1e-11.

Convert Femtometer to other length units

Show all Femtometer conversions

Sources & references

Conversion factor (1 fm = 1e-13 cm) verified against the following authoritative sources:

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