LocalToolsOffline browser tools collection

Category: Converters

Roman Numeral Converter

System ideaMissing a tool?

Convert numbers to Roman numerals and back, offline

Convert a whole number from 1 to 3999 into standard Roman numerals, or read a numeral such as MMXXVI back as a number. Runs entirely in your browser.

Supported range: 1–3999

ResultMMXXVI

Everything on this page is processed in your browser. Nothing is uploaded.

What this tool does

Standard Roman numerals combine seven letters with the subtractive pairs IV, IX, XL, XC, CD and CM, which is why 1994 is MCMXCIV rather than a long run of repeated letters. This converter writes numerals in that canonical form and, reading the other way, accepts only canonical spellings, so a typo like IIII is reported instead of being silently rounded into IV.

How to use it

  1. Pick the direction: number to numeral, or numeral to number.
  2. Type the value you have.
  3. Read the converted result underneath.

Privacy

This tool runs entirely in your browser. Your input is never uploaded, stored or shared — closing the tab removes it.

Frequently asked questions

Is anything I type sent to a server?
No. The conversion is a few lines of JavaScript running in your browser tab, so the value stays on your device.
Why does the tool stop at 3999?
Above 3999 the standard letters run out and larger values need overlines or other notations that have no single agreed spelling, so this tool keeps to the range everyone reads the same way.
Is there a Roman numeral for zero?
No. The system has no zero and no negative numbers, which is why the supported range starts at 1.

Back to all tools