# Ordinal to words en

`ordinal-to-words-en` · version 1.0.0 · Numbers & math · free, no key needed

Spell an integer ordinal in English words and return the styled ordinal text.

**Use when you need to: ordinal number to English words · spell 21st in words · convert integer to ordinal words.**

## Decide before calling

Read the [versioned contract](/v1/tools/ordinal-to-words-en/versions/1.0.0) and the supported scope below. Reuse `ordinal-to-words-en@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 `ordinal-to-words-en@1.0.0` for ordinal number to English words. 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

- ordinal number to English words
- spell 21st in words
- convert integer to ordinal words
- write a negative ordinal in English
- English ordinal name generator
- number as first second or third

## Not supported

- cardinal decimal wording
- parse ordinal words
- ordinal suffix only

## Behavior

- Uses the documented ComputeFirst English short-scale grammar through undecillion; this is a deterministic house grammar, not an authoritative linguistic standard.
- Options default to hyphenate=true, use_and=false, and negative_word="minus"; callers can select every style choice explicitly.
- Input and output are locale-independent ASCII; no trimming, case folding, host locale, or binary floating-point conversion.

## Input

- `value` (string, required): min length 1; max length 40
- `hyphenate` (boolean, optional): default `true`
- `use_and` (boolean, optional): default `false`
- `negative_word` (one of "minus", "negative", optional): default `"minus"`

## Output

- `text` (string, required): min length 1; max length 2048
- `standard_version` (constant "compute-first-english-number-words-1.0.0", required)

## Limits

- max input bytes: 40
- max integer digits: 39
- max output bytes: 581

## Example

Request input:

```json
{
  "value": "21"
}
```

Response:

```json
{
  "result": {
    "text": "twenty-first",
    "standard_version": "compute-first-english-number-words-1.0.0"
  }
}
```

## How to call it

### MCP

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

```json
{
  "id": "ordinal-to-words-en",
  "version": "1.0.0",
  "input": {
    "value": "21"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/ordinal-to-words-en/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"value":"21"}'
```

The machine-readable contract is at [/v1/tools/ordinal-to-words-en/versions/1.0.0](/v1/tools/ordinal-to-words-en/versions/1.0.0).

### CLI

```sh
node cli.mjs run ordinal-to-words-en 1.0.0 --input input.json --base-url https://computefirst.net
```

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

## Related tools

- [Number to words en](/tools/number-to-words-en): Spell an integer or exact decimal in English words and return the styled text.
- [Number engineering format](/tools/number-engineering-format): Format an exact decimal in scientific or engineering notation with explicit precision and rounding.
- [Roman numeral convert](/tools/roman-numeral-convert): Convert integers 1–3999 to canonical Roman numerals and strictly parse canonical numerals back to integers.
- [Classification metrics compute](/tools/classification-metrics-compute): Compute exact binary-classification metrics from integer confusion-matrix counts as reduced fractions or null.
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- [Graph path weight check](/tools/graph-path-weight-check): Check that a path of edge IDs walks source to target in a weighted digraph and sums to the claimed exact weight.