Roman Numeral Converter

Convert numbers to Roman numerals and Roman numerals to numbers (1–3999) — free and instant.

About

About the Roman Numeral Converter

Converts a whole number from 1 to 3999 into Roman numerals, and reads a Roman numeral back into a number.

Students use it to check homework on Roman numerals, while people planning events use it to work out how a wedding date or an anniversary year is written in numerals for an invitation or engraving. It's one of many free converters on Toolapt, and like every tool here, it's free to use with no sign-up and no limit on how many times you run it.

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Guide

Using the Roman Numeral Converter

  1. 1

    Step 1

    To convert a number to Roman numerals: type it into the Number field and click "Number to Roman".

  2. 2

    Step 2

    To convert a Roman numeral back to a number: type it into the Roman numeral field and click "Roman to number".

  3. 3

    Step 3

    Read the result, or copy the numeral with the "Copy numeral" button.

  4. 4

    Step 4

    Click Clear to reset both fields and start over.

  • Converts in both directions — number to Roman numeral, and Roman numeral back to number — in one tool
  • Supports the full classical range from 1 to 3999, matching what standard Roman numerals can represent
  • Uses correct subtractive notation (IV, IX, XL, XC, CD, CM), not just repeated symbols
  • Validates Roman numeral input and flags a value that isn't a well-formed numeral
  • Works entirely in your browser — no installs and no sign-up
  • Free to use, with no limit on how many times you run it
  • Fully responsive, so it works just as well on a phone as on a desktop

Students

Students use the Roman Numeral Converter for checking homework or practicing how Roman numerals work before a test.

Event planners

Event planners use the Roman Numeral Converter for working out how a wedding date or anniversary year should be written in numerals for an invitation or engraving.

Writers and editors

Writers and editors use the Roman Numeral Converter for checking chapter numbers, movie sequel numbers or historical dates written as numerals.

Anyone curious about a numeral

Anyone curious about a numeral uses the Roman Numeral Converter for decoding a numeral seen on a clock face, building cornerstone or film credit.

Examples

Roman Numeral Converter examples

3 worked examples

01

A year in numerals

Enter 2026 and click Number to Roman to get MMXXVI — 2000 as MM, then 26 as XXVI.

02

Subtractive notation

Enter 1994 to get MCMXCIV, using the subtractive forms for 900 (CM), 90 (XC) and 4 (IV) instead of long strings of repeated symbols.

03

Converting back to a number

Enter LVIII into the Roman numeral field and click Roman to number to get 58 — L (50) plus VIII (8).

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FAQ

Frequently asked questions

Quick answers to common questions about the Roman Numeral Converter.

What does the Roman Numeral Converter do?

It converts a whole number from 1 to 3999 into Roman numerals, and converts a Roman numeral back into an ordinary number.

Is the Roman Numeral Converter free to use?

Yes. It's free, with no sign-up, no watermark and no limit on how many times you use it.

Is my input safe when I use this tool?

Yes. The number or numeral you enter is processed entirely on your own device — nothing is sent to a server.

Why is the range limited to 1–3999?

Standard Roman numerals don't have a symbol for zero or for values of 4000 and above without special notation, so 1 to 3999 is the range the classical system can represent with the usual letters (I, V, X, L, C, D, M).

What happens if I type an invalid Roman numeral?

The converter checks that the letters form a well-formed numeral under standard rules and shows a message if what you typed doesn't match a valid Roman numeral.

Does it use subtractive notation like IV and IX?

Yes. Values like 4, 9, 40, 90, 400 and 900 use the standard subtractive forms (IV, IX, XL, XC, CD, CM) rather than four or nine repeated symbols.

Can I use the Roman Numeral Converter on my phone?

Yes. The page is fully responsive and works on mobile, tablet and desktop browsers alike.

Does the Roman Numeral Converter have any limitations?

It covers the standard 1–3999 range used in everyday numerals; extended historical notations for larger numbers aren't supported.

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