Convert Hectometer to Femtometer
Convert hectometers to femtometers instantly. 1 hectometer = 1e+17 femtometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Femtometer to Hectometer converter for the reverse conversion.
Units explained
Hectometer
A hectometer is a metric unit of length equal to one hundred meters (100 m). It is occasionally used in sports, agricultural surveying, and some European real-estate contexts.
The hectometer was defined alongside the meter when France adopted the metric system in 1795, using the SI prefix hecto- (from Greek hekaton, hundred) to denote multiplication by 100.
Hectometers appear in some sports contexts (the 100 m sprint is technically 1 hm), in agriculture (parcel sizes in some European nations), and in atmospheric science. Most contexts now use meters or kilometers instead.
Adopted in 1795 in France; ratified through the Metre Convention of 1875; remains a defined SI prefix unit although rarely used outside specialised contexts.
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 The name fermi (after Enrico Fermi) was used informally from the 1950s but officially superseded by femtometer.
Hectometer to Femtometer conversion formula
The relationship between hectometers and femtometers:
To convert hectometers to femtometers, multiply the value in hectometers by 1e+17. To reverse, multiply femtometers by 1e-17.
How to use this converter
Type a value into the calculator. The result in femtometers updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Femtometer to Hectometer converter for the reverse direction.
Step-by-step: convert hectometers to femtometers
- Write down the value in hectometers (hm).
- Multiply that value by the factor 1e+17.
- The product is the equivalent value in femtometers (fm).
- To reverse, multiply the femtometer value by 1e-17.
Worked examples
Example 1 — Convert 1 hm to fm:
1 × 1e+17 = 1e+17 fm
Example 2 — Convert 100 hm to fm:
100 × 1e+17 = 1e+19 fm
Hectometer to Femtometer conversion table
Standard reference values for converting hectometers to femtometers:
| Hectometer [hm] | Femtometer [fm] |
|---|---|
| 0.01 | 1e+15 |
| 0.1 | 1e+16 |
| 1 | 1e+17 |
| 2 | 2e+17 |
| 3 | 3e+17 |
| 4 | 4e+17 |
| 5 | 5e+17 |
| 10 | 1e+18 |
| 20 | 2e+18 |
| 30 | 3e+18 |
| 40 | 4e+18 |
| 50 | 5e+18 |
| 100 | 1e+19 |
| 500 | 5e+19 |
| 1000 | 1e+20 |
Frequently asked questions
How many femtometers is 1 hectometer?
How do I convert hectometers to femtometers?
How do I convert femtometers back to hectometers?
How many femtometers is 100 hectometers?
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Sources & references
Conversion factor (1 hm = 1e+17 fm) 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 Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.