Convert Square Kilometer to Square Attometer
Convert square kilometers to square attometers instantly. 1 square kilometer = 1e+42 square attometer — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Square Attometer 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 Attometer
A square attometer is a metric unit of area equal to 10⁻³⁶ m². It is used in theoretical particle physics when discussing cross-sections at the sub-femtometer scale.
Derived by squaring the attometer (10⁻¹⁸ m). The atto- prefix was adopted by the CGPM in 1964 from the Danish 'atten' (eighteen), denoting 10⁻¹⁸.
Square attometers can appear in particle physics literature comparing extremely small interaction cross-sections, though more often barns (10⁻²⁸ m²) are used at this scale.
SI prefix atto- adopted in 1964; remains a defined unit, rarely used in practice.
Square Kilometer to Square Attometer conversion formula
The relationship between square kilometers and square attometers:
To convert square kilometers to square attometers, multiply the value in square kilometers by 1e+42. To reverse, multiply square attometers by 1e-42.
How to use this converter
Type a value into the calculator. The result in square attometers 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 Attometer to Square Kilometer converter for the reverse direction.
Step-by-step: convert square kilometers to square attometers
- Write down the value in square kilometers (km²).
- Multiply that value by the factor 1e+42.
- The product is the equivalent value in square attometers (am²).
- To reverse, multiply the square attometer value by 1e-42.
Worked examples
Example 1 — Convert 1 km² to am²:
1 × 1e+42 = 1e+42 am²
Example 2 — Convert 100 km² to am²:
100 × 1e+42 = 1e+44 am²
Square Kilometer to Square Attometer conversion table
Standard reference values for converting square kilometers to square attometers:
| Square Kilometer [km²] | Square Attometer [am²] |
|---|---|
| 0.01 | 1e+40 |
| 0.1 | 1e+41 |
| 1 | 1e+42 |
| 2 | 2e+42 |
| 3 | 3e+42 |
| 4 | 4e+42 |
| 5 | 5e+42 |
| 10 | 1e+43 |
| 20 | 2e+43 |
| 30 | 3e+43 |
| 40 | 4e+43 |
| 50 | 5e+43 |
| 100 | 1e+44 |
| 500 | 5e+44 |
| 1000 | 1e+45 |
Frequently asked questions
How many square attometers is 1 square kilometer?
How do I convert square kilometers to square attometers?
How do I convert square attometers back to square kilometers?
How many square attometers is 100 square kilometers?
Popular area unit conversions
Convert Square Kilometer to other area units
Show all Square Kilometer conversions
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+42 am²) 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.