# Byte size convert

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

Convert a non-negative integer byte size between IEC binary units as an exact rational.

**Use when you need to: bytesize convert · convert binary byte units · convert kibibytes to bytes.**

## Supported

- bytesize convert
- convert binary byte units
- convert kibibytes to bytes

## Not supported

- SI kB/MB/GB
- bits
- signed byte sizes
- decimal megabytes
- fuzzy unit names

## Behavior

- value is a non-negative canonical integer string amount in the from unit; -0 is accepted and canonicalized to 0.
- from and to are exactly one of B, KiB, MiB, GiB, TiB using the BYTE_SIZE table (powers of 1024).
- The result is the reduced rational (value * from_bytes) / to_bytes expressed in to units.
- Zero is numerator 0 over denominator 1. Negative sizes, SI decimal prefixes, and bit units are rejected.
- Input integers and the reduced numerator and denominator may have at most 1000 digits excluding sign.

## Input

- `value` (string, required): max length 1001; pattern `^-?(0|[1-9][0-9]*)$`
- `from` (one of "B", "KiB", "MiB", "GiB", "TiB", required)
- `to` (one of "B", "KiB", "MiB", "GiB", "TiB", required)

## Output

- `numerator` (string, required): pattern `^(0|[1-9][0-9]*)$`
- `denominator` (string, required): pattern `^[1-9][0-9]*$`

## Limits

- max digits: 1000
- units: ["B","KiB","MiB","GiB","TiB"]

## Example

Request input:

```json
{
  "value": "1",
  "from": "KiB",
  "to": "B"
}
```

Response:

```json
{
  "result": {
    "numerator": "1024",
    "denominator": "1"
  }
}
```

## How to call it

### MCP

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

```json
{
  "id": "bytesize-convert",
  "version": "1.0.0",
  "input": {
    "value": "1",
    "from": "KiB",
    "to": "B"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/bytesize-convert/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"value":"1","from":"KiB","to":"B"}'
```

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

### CLI

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

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

## Related tools

- [Byte size compare](/tools/bytesize-compare): Compare two non-negative integer byte sizes by exact byte amounts.
- [Byte size add](/tools/bytesize-add): Add non-negative integer byte-size terms in mixed IEC units and return the exact sum in a chosen unit.
- [Length convert](/tools/length-convert): Convert a canonical integer length between exact SI and international customary units.
- [Mass convert](/tools/mass-convert): Convert a canonical integer mass amount between exact nanogram-based units as a reduced rational.
- [Mass add](/tools/mass-add): Add mixed-unit canonical integer mass amounts and express the sum in a target unit as a reduced rational.
- [Temperature compare](/tools/temperature-compare): Compare two temperatures in C, F, or K by converting both to Kelvin rationals.