# Square kilometers to Square meters (km² to m²)

> Convert square kilometers to square meters: 1 km² = 1000000 m². Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

- Page id: `square-km-to-square-meters` · Quantity: Area (`area`, base unit m2) · Tool: `convert_units`
- Canonical page: https://tttkmbb.com/conversion/square-km-to-square-meters · This document: https://tttkmbb.com/conversion/square-km-to-square-meters.md · JSON: https://tttkmbb.com/conversion/square-km-to-square-meters.json (add `?value=` for a result)

## Formula

- `1 km² = 1000000 m²`
- `square meters = square kilometers × 1000000`
- Reverse: `square kilometers = square meters × 0.000001`

The factor follows from the SI definitions of both units (NIST SP 811); values below are rounded to 6 significant figures, the API returns up to 12.

## Worked examples

- 5 km² = 5000000 m²
- 12.5 km² = 12500000 m²
- 100 km² = 100000000 m²

## Conversion table

| Square kilometers (km²) | Square meters (m²) |
| --- | --- |
| 1 | 1000000 |
| 2 | 2000000 |
| 3 | 3000000 |
| 4 | 4000000 |
| 5 | 5000000 |
| 6 | 6000000 |
| 7 | 7000000 |
| 8 | 8000000 |
| 9 | 9000000 |
| 10 | 10000000 |
| 15 | 15000000 |
| 20 | 20000000 |
| 25 | 25000000 |
| 30 | 30000000 |
| 40 | 40000000 |
| 50 | 50000000 |
| 75 | 75000000 |
| 100 | 100000000 |
| 200 | 200000000 |
| 250 | 250000000 |
| 500 | 500000000 |
| 1000 | 1000000000 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=km2&to_unit=m2` → unified JSON envelope with `result.values.result`, `formula`, `factor`, `sources`, `freshness`
- MCP: server `https://tttkmbb.com/mcp`, tool `convert_units` with `{"value":5,"from_unit":"km2","to_unit":"m2"}`
- All area units: https://tttkmbb.com/api/v1/units?quantity=area · full converter: [Area Converter](https://tttkmbb.com/conversion/area.md)
- Authentication: none. Freshness: `static` (fixed conversion factors).

## FAQ

**How many square meters are in one square kilometer?**

1 km² = 1000000 m². The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.

**What is the formula to convert square kilometers to square meters?**

Multiply the value in square kilometers by 1000000: square meters = square kilometers × 1000000. For example, 5 km² = 5000000 m².

**How do I convert square meters back to square kilometers?**

Multiply by the inverse factor 0.000001 (square kilometers = square meters × 0.000001), or use the square meters-to-square kilometers page.

## Related conversions

- [Square meters to square kilometers](https://tttkmbb.com/conversion/square-meters-to-square-km.md) (reverse)
- [Square meters to Square feet](https://tttkmbb.com/conversion/square-meters-to-square-feet.md)
- [Square feet to Square meters](https://tttkmbb.com/conversion/square-feet-to-square-meters.md)
- [Acres to Hectares](https://tttkmbb.com/conversion/acres-to-hectares.md)
- [Hectares to Acres](https://tttkmbb.com/conversion/hectares-to-acres.md)
- [Acres to Square meters](https://tttkmbb.com/conversion/acres-to-square-meters.md)
- [Square meters to Acres](https://tttkmbb.com/conversion/square-meters-to-acres.md)
- [Square kilometers to Square miles](https://tttkmbb.com/conversion/square-km-to-square-miles.md)
- [Square miles to Square kilometers](https://tttkmbb.com/conversion/square-miles-to-square-km.md)

## Data Sources

- NIST Special Publication 811 – Guide for the Use of the International System of Units (SI), Appendix B conversion factors — https://www.nist.gov/pml/special-publication-811 (standard, retrieved 2026-09-24)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-24)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-24)