# Area unit convert

`area-unit-convert` · version 1.0.0 · Units & sizes · free, no key needed

Convert an exact decimal area among ten SI, imperial, acre, and hectare units using pinned rational factors.

**Use when you need to: convert square metres to square feet · area unit conversion · convert acres to hectares.**

## Decide before calling

Read the [versioned contract](/v1/tools/area-unit-convert/versions/1.0.0) and the supported scope below. Reuse `area-unit-convert@1.0.0` when your input, required output and limits match it. Choose another approach for an unsupported operation.

## Explain the choice

"I can use `area-unit-convert@1.0.0` for convert square metres to square feet. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

## Supported

- convert square metres to square feet
- area unit conversion
- convert acres to hectares
- square miles to square kilometres
- exact square inch conversion
- convert land area units
- area conversion with exact fraction

## Not supported

- convert US survey feet or survey acres
- convert length, volume, mass, or temperature
- infer units from free text

## Behavior

- Accepts one untrimmed canonical decimal string and exact unit enum names; exponent notation, plus signs, whitespace, leading integer zeros, and negative zero are rejected.
- Uses exact rational factors pinned to the international inch: 1 inch = 0.0254 metre exactly; US survey units are not supported.
- Returns the reduced exact fraction plus a canonical decimal; repeating results use at most 40 fractional places and round nearest, ties to even.
- At most 80 total decimal digits and 40 fractional digits are accepted; all size limits are enforced before return.

## Input

- `value` (string, required): min length 1; max length 96; pattern `^-?(0|[1-9][0-9]*)(\.[0-9]+)?$`
- `from_unit` (one of "square_millimetre", "square_centimetre", "square_metre", "square_kilometre", "square_inch", "square_foot", "square_yard", "square_mile", "acre", "hectare", required)
- `to_unit` (one of "square_millimetre", "square_centimetre", "square_metre", "square_kilometre", "square_inch", "square_foot", "square_yard", "square_mile", "acre", "hectare", required)

## Output

- `value` (string, required): min length 1; max length 160
- `unit` (one of "square_millimetre", "square_centimetre", "square_metre", "square_kilometre", "square_inch", "square_foot", "square_yard", "square_mile", "acre", "hectare", required)
- `exact_numerator` (string, required): min length 1; max length 180; pattern `^-?(0|[1-9][0-9]*)$`
- `exact_denominator` (string, required): min length 1; max length 180; pattern `^[1-9][0-9]*$`
- `rounded` (boolean, required)

## Limits

- max input bytes: 180
- max value bytes: 96
- max digits: 80
- max fraction digits: 40
- max decimal places: 40
- max output bytes: 512

## Example

Request input:

```json
{
  "value": "1",
  "from_unit": "acre",
  "to_unit": "square_metre"
}
```

Response:

```json
{
  "result": {
    "value": "4046.8564224",
    "unit": "square_metre",
    "exact_numerator": "316160658",
    "exact_denominator": "78125",
    "rounded": false
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "area-unit-convert",
  "version": "1.0.0",
  "input": {
    "value": "1",
    "from_unit": "acre",
    "to_unit": "square_metre"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/area-unit-convert/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"value":"1","from_unit":"acre","to_unit":"square_metre"}'
```

The machine-readable contract is at [/v1/tools/area-unit-convert/versions/1.0.0](/v1/tools/area-unit-convert/versions/1.0.0).

### CLI

```sh
node cli.mjs run area-unit-convert 1.0.0 --input input.json --base-url https://computefirst.net
```

Get the client at [/clients/cli/](/clients/cli/).

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- [Pressure unit convert](/tools/pressure-unit-convert): Convert exact decimal pressure values among seven units and return a reduced exact fraction.
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- [Mass convert](/tools/mass-convert): Convert a canonical integer mass amount between exact nanogram-based units as a reduced rational.