Roman numerals: convert numbers to Roman numerals and back

$0.01 per call · failed calls are never charged · no account or subscription: pay per call with a card key or USDC

Convert a number (1-3999) to Roman numerals, or Roman numerals back to a number. Give either number or roman. Use for dates, outlines and puzzles.

Run it free (25 free calls) Buy credits by card (from $1) Example result (JSON)

Try it with your own inputs

1 to 3999

Uses one of your 25 free calls. Nothing is charged, and a call that fails is not counted.

Inputs

NameTypeDescription
numberinteger1 to 3999
romanstringRoman numerals to read

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/number/roman?number=2026"

Or one of your 25 free calls, no key:

curl "https://tools.funwords.eu/number/roman?number=2026&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "number": 2026,
  "roman": "MMXXVI"
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is number_roman, and the first 25 successful calls are free:

https://tools.funwords.eu/mcp

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