# Area Converter

> Converts areas between metric (mm² to km², hectare) and US/imperial units (in², ft², yd², acre, mi²) using exact factors (1 ft² = 0.09290304 m², 1 acre = 4046.8564224 m²).

- Calculator id: `area` · Category: Unit Conversion (`conversion`) · Tool name: `convert_area`
- Canonical page: https://tttkmbb.com/conversion/area · This document: https://tttkmbb.com/conversion/area.md · JSON definition: https://tttkmbb.com/conversion/area.json

## Purpose

Converts areas between metric (mm² to km², hectare) and US/imperial units (in², ft², yd², acre, mi²) using exact factors (1 ft² = 0.09290304 m², 1 acre = 4046.8564224 m²).

**Use when:** You need land, floor or surface area in another unit, e.g. square feet to square metres, acres to hectares or square miles to square kilometres.

**Do not use when:** You need to compute an area from dimensions (use rectangle, circle or triangle-area) or material quantities for a floor (use flooring).

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `value` | number |  | required | Amount to convert, expressed in from_unit. |
| `from_unit` | enum: mm2 \| cm2 \| m2 \| ha \| km2 \| in2 \| ft2 \| yd2 \| acre \| mi2 |  | required | Unit of the input value. Accepted symbols: mm2, cm2, m2, ha, km2, in2, ft2, yd2, acre, mi2; spelled-out names and common abbreviations are accepted too. |
| `to_unit` | enum: mm2 \| cm2 \| m2 \| ha \| km2 \| in2 \| ft2 \| yd2 \| acre \| mi2 |  | required | Unit to convert into (same symbols as from_unit). |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `result` | number |  | Converted value expressed in to_unit (rounded to 6 decimals; see result_text for very small or very large values). |
| `result_text` | string |  | The conversion as text with 6 significant figures, e.g. "5 mi = 8.04672 km". |
| `formula` | string |  | Relation used, e.g. "1 mi = 1.609344 km". |
| `factor` | number |  | Multiplier from from_unit to to_unit (result = value × factor); absent for non-linear conversions. |
| `conversion_table` | object |  | The input value expressed in every supported area unit (6 significant figures), keyed by unit symbol. |

## Formula

`result = value × factor, factor = (1 from_unit in m2) / (1 to_unit in m2)`

## 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 2026-09-23)
- BIPM – The International System of Units (SI Brochure, 9th edition) — https://www.bipm.org/en/publications/si-brochure (standard, retrieved 2026-09-23)
- Wikipedia – Conversion of units — https://en.wikipedia.org/wiki/Conversion_of_units (reference, retrieved 2026-09-23)

Data freshness: `static`. Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output.

## API

- `GET https://tttkmbb.com/api/v1/calculate/area?value=…&from_unit=…&to_unit=…`
- `POST https://tttkmbb.com/api/v1/calculate/area` with JSON body `{"inputs": {…}}`
- Response: unified envelope (`success`, `request`, `result.values`, `result.units`, `sources`, `freshness`, `timestamp`, `next_actions`, `links`); see https://tttkmbb.com/docs/response-format.md
- Schema: https://tttkmbb.com/api/v1/calculators/area · OpenAPI operationId `convert_area` in https://tttkmbb.com/openapi.json
- Authentication: none. Rate limit: fair use, see https://tttkmbb.com/docs/rate-limits.md.

## MCP

- Server: `https://tttkmbb.com/mcp` (Streamable HTTP, JSON-RPC 2.0, no auth)
- Tool:  `run_calculator` with `{"calculator_id": "area", "inputs": {…}}`

## Example

- 1 acre to square feet: inputs `{"value":1,"from_unit":"acre","to_unit":"ft2"}` → `{"result":43560,"factor":43560,"formula":"1 acre = 43560 ft²","conversion_table":{"m2":4046.86,"ha":0.404686}}`
- 120 m² to square feet: inputs `{"value":120,"from_unit":"m2","to_unit":"ft2"}` → `{"result":1291.66925,"conversion_table":{"yd2":143.519,"acre":0.0296526}}`

```
GET https://tttkmbb.com/api/v1/calculate/area?value=1&from_unit=acre&to_unit=ft2
```

## Limitations

You need to compute an area from dimensions (use rectangle, circle or triangle-area) or material quantities for a floor (use flooring). All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**How do I enter square units?**

Use m2, ft2, km2 (or m², sq ft, square feet, sqm and similar spellings); the enum values are the ASCII forms.

**Is the acre exact?**

Yes: the international acre is 4046.8564224 m² (66 × 660 international feet). The US survey acre differs by about 4 parts per million and is not used here.

## Related

- [Rectangle Calculator](https://tttkmbb.com/geometry/rectangle.md) — Compute area from side lengths first.
- [Flooring Calculator](https://tttkmbb.com/construction/flooring.md) — Estimate flooring from a floor area.
- [Length Converter](https://tttkmbb.com/conversion/length.md) — Convert the underlying lengths.