---
title: "Roman Numeral Converter"
method: GET
path: "/api/calc/roman-numeral-converter"
tags: ["Conversion"]
---

# Roman Numeral Converter

`GET /api/calc/roman-numeral-converter`

## Request

- Base URL: `https://calcbright.com`
- URL: `https://calcbright.com/api/calc/roman-numeral-converter`
- Auth: none declared

MCMXCIX is 1999 and 2026 is MMXXVI. Convert any number from 1 to 3999 into Roman numerals, or decode a numeral back to a number, with each symbol explained.

## Query parameters

- `mode` 'toRoman' | 'toNumber': Convert
- `number` number: Number
- `roman` string: Roman numeral

## Response `200`

Calculation result

- CalcOutput
  - `ok` boolean
  - `tool` string
  - `name` string
  - `url` string: Open this link to see the full calculation
  - `inputs` object
  - `summary` string: Plain-text answer
  - `details` string
  - `result` object
  - `errors` object

## Other responses

- `400`: Invalid input (see errors)

---

[API](https://skmtc.dev/calcbright/apis/calcbright-calculator-api.md) · [All operations](https://skmtc.dev/calcbright/apis/calcbright-calculator-api/llms.txt) · [OpenAPI document](https://skmtc.dev/calcbright/apis/calcbright-calculator-api/revisions/f58229e56e58?raw)