# Square meters to Acres (m² to acre)

> Convert square meters to acres: 1 m² = 0.000247105 acre. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.

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

## Formula

- `1 m² = 0.000247105 acre`
- `acres = square meters × 0.0002471053815`
- Reverse: `square meters = acres × 4046.856422`

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 m² = 0.00123553 acre
- 12.5 m² = 0.00308882 acre
- 100 m² = 0.0247105 acre

## Conversion table

| Square meters (m²) | Acres (acre) |
| --- | --- |
| 1 | 0.000247105 |
| 2 | 0.000494211 |
| 3 | 0.000741316 |
| 4 | 0.000988422 |
| 5 | 0.00123553 |
| 6 | 0.00148263 |
| 7 | 0.00172974 |
| 8 | 0.00197684 |
| 9 | 0.00222395 |
| 10 | 0.00247105 |
| 15 | 0.00370658 |
| 20 | 0.00494211 |
| 25 | 0.00617763 |
| 30 | 0.00741316 |
| 40 | 0.00988422 |
| 50 | 0.0123553 |
| 75 | 0.0185329 |
| 100 | 0.0247105 |
| 200 | 0.0494211 |
| 250 | 0.0617763 |
| 500 | 0.123553 |
| 1000 | 0.247105 |

## API

- `GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=m2&to_unit=acre` → 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":"m2","to_unit":"acre"}`
- 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 acres are in one square meter?**

1 m² = 0.000247105 acre. 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 meters to acres?**

Multiply the value in square meters by 0.0002471053815: acres = square meters × 0.0002471053815. For example, 5 m² = 0.00123553 acre.

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

Multiply by the inverse factor 4046.856422 (square meters = acres × 4046.856422), or use the acres-to-square meters page.

## Related conversions

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