Square metric area unit.
Square Kilometers to Square Gigameters Converter — km2 to Gm2
Convert Square Kilometer (km2) to Square Gigameter (Gm2) using the exact conversion factor (1 square kilometer = 1e-12 square gigameter). See the formula, worked examples, conversion table, history, and common uses.
Square Kilometers to Square Gigameters converter
Converter
Area Converter
Convert land, construction, mapping, survey, and scientific area units.
Context values
Some unit families need one extra value for a physically accurate result.
Square metric area unit.
Result = input x 1e+6 / 1e+18.
Area uses the square meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Square Kilometers to Square Gigameters
Comparing Square Kilometer and Square Gigameter is common in agriculture and real estate, where US land is typically measured in acres and most of the rest of the world uses hectares. Square Kilometer is most often used for national and regional land-area statistics.
Formula
square gigameters = square kilometers × 1e-12
This factor comes from each unit's defined relationship to the category's base unit: 1 square kilometer equals 1000000 base units, and 1 square gigameter equals 1e+18 base units, so dividing one by the other gives the direct square kilometer-to-square gigameter factor of 1e-12.
Simple example
1 km2 × 1e-12 = 1e-12 Gm2
1 square kilometer = 1e-12 square gigameters.
Real-world example
10 km2 × 1e-12 = 1e-11 Gm2
10 square kilometers = 1e-11 square gigameters.
Conversion table
| Square Kilometer (km2) | Square Gigameter (Gm2) |
|---|---|
| 1 km2 | 1e-12 Gm2 |
| 5 km2 | 5e-12 Gm2 |
| 10 km2 | 1e-11 Gm2 |
| 25 km2 | 2.5e-11 Gm2 |
| 50 km2 | 5e-11 Gm2 |
| 100 km2 | 1e-10 Gm2 |
Reverse conversion: Square Gigameter to Square Kilometer
1e-12 Gm2 × 1e+12 = 1 km2
1e-12 square gigameters = 1 square kilometer.
square kilometers = square gigameters × 1e+12
For a page dedicated to this direction, see Square Gigameter to Square Kilometer.
Understanding the Square Kilometer
Square Kilometer (km2) measures area. A square kilometer is one million square meters — the area of a 1 km × 1 km square. It is classified as a SI derived (metric prefix) unit.
Where it's used: Used worldwide for city, region, and country-scale area reporting.
Uses of the Square Kilometer today
- National and regional land-area statistics
- City and urban planning at large scale
- Geography and cartography
History of the Square Kilometer
Like other metric-prefixed area units, the square kilometer follows automatically from the kilometer once the meter was standardized in the 1790s French metric reform.
Historical origin. Square Kilometer was not the invention of a single named person; it developed through the process described above.
Understanding the Square Gigameter (Gm2)
Square metric area unit.
Square Kilometer — sources
- BIPM SI Brochure — Coherent derived units — Basis for metric-prefixed area units.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many square gigameters are in 1 square kilometer?
1 square kilometer equals 1e-12 square gigameters, using the exact defined conversion factor rather than an estimate.
How do I convert square kilometer to square gigameter?
Multiply the square kilometer value by 1e-12. The converter above does this instantly to whatever precision you set.
How do I convert square gigameter back to square kilometer?
Use the reverse factor: 1 square gigameter equals 1e+12 square kilometers. You can also use the swap control in the converter above to flip the direction instantly.
What is a square kilometer?
Square Kilometer (km2) measures area. A square kilometer is one million square meters — the area of a 1 km × 1 km square. It is classified as a SI derived (metric prefix) unit.
What is a square gigameter?
Square Gigameter (Gm2) is a unit of area.
Is the square kilometer to square gigameter conversion exact?
Yes. Both square kilometer and square gigameter are defined by fixed standards rather than physical artifacts, so the factor of 1e-12 used above is exact to as many digits as you choose to display.
Where is the square kilometer still used today?
Used worldwide for city, region, and country-scale area reporting.