Convert Square Kilometer to Square Femtometer
Convert square kilometers to square femtometers instantly. 1 square kilometer = 1e+36 square femtometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Square Femtometer to Square Kilometer converter for the reverse conversion.
Units explained
Square Kilometer
A square kilometer is a metric unit of area equal to 1,000,000 m² (one million square meters), or 100 hectares. It is used for measuring large land areas, regional geography, and country-scale statistics.
Derived by squaring the kilometer (1000 m). The kilo- prefix comes from the Greek 'chilioi' (thousand).
Square kilometers express the area of cities, districts, lakes, forests, and entire countries. India's total area is approximately 3,287,263 km². 1 km² equals 100 hectares or about 247.105 acres.
Kilometer has been part of the metric system since 1795.
Square Femtometer
A square femtometer is a metric unit of area equal to 10⁻³⁰ m². It is used in nuclear and particle physics to describe interaction cross-sections at the nuclear scale.
Derived by squaring the femtometer (10⁻¹⁵ m), historically known as the fermi after physicist Enrico Fermi.
Square femtometers are equivalent to 0.01 barn. They appear in particle physics literature comparing strong interaction cross-sections and hadron sizes.
Femtometer adopted into SI in 1964; the fermi nomenclature predates this from mid-20th century nuclear physics.
Square Kilometer to Square Femtometer conversion formula
The relationship between square kilometers and square femtometers:
To convert square kilometers to square femtometers, multiply the value in square kilometers by 1e+36. To reverse, multiply square femtometers by 1e-36.
How to use this converter
Type a value into the calculator. The result in square 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 Square Femtometer to Square Kilometer converter for the reverse direction.
Step-by-step: convert square kilometers to square femtometers
- Write down the value in square kilometers (km²).
- Multiply that value by the factor 1e+36.
- The product is the equivalent value in square femtometers (fm²).
- To reverse, multiply the square femtometer value by 1e-36.
Worked examples
Example 1 — Convert 1 km² to fm²:
1 × 1e+36 = 1e+36 fm²
Example 2 — Convert 100 km² to fm²:
100 × 1e+36 = 1e+38 fm²
Square Kilometer to Square Femtometer conversion table
Standard reference values for converting square kilometers to square femtometers:
| Square Kilometer [km²] | Square Femtometer [fm²] |
|---|---|
| 0.01 | 1e+34 |
| 0.1 | 1e+35 |
| 1 | 1e+36 |
| 2 | 2e+36 |
| 3 | 3e+36 |
| 4 | 4e+36 |
| 5 | 5e+36 |
| 10 | 1e+37 |
| 20 | 2e+37 |
| 30 | 3e+37 |
| 40 | 4e+37 |
| 50 | 5e+37 |
| 100 | 1e+38 |
| 500 | 5e+38 |
| 1000 | 1e+39 |
Frequently asked questions
How many square femtometers is 1 square kilometer?
How do I convert square kilometers to square femtometers?
How do I convert square femtometers back to square kilometers?
How many square femtometers is 100 square kilometers?
Popular area unit conversions
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Metric / SI (15 units)
Imperial / US Customary (15 units)
US Survey (5 units)
Indian Subcontinent (16 units)
Other Regional (10 units)
Scientific / Physics (5 units)
Sources & references
Conversion factor (1 km² = 1e+36 fm²) 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.