Roman Numeral Converter
Convert numbers to Roman numerals and Roman numerals back to numbers, live, with...Convert numbers to Roman numerals and Roman numerals back to numbers, live, with a step-by-step breakdown, strict validation, and a full reference cha...
Updated
How it is built
2,024 = MM + XX + IV = MMXXIV
Try an example
Roman numeral chart
Subtractive pairs
The rules in one place
- A symbol can repeat at most three times in a row, so 3 is III but 4 is IV.
- V, L, and D are never repeated, because two of them equal the next symbol up.
- A smaller symbol before a larger one is subtracted, but only IV, IX, XL, XC, CD, and CM are allowed.
- The standard range is 1 to 3,999. A bar over a numeral (a vinculum) multiplies it by 1000, reaching 3,999,999.
Quick answer
To convert a number to a Roman numeral, split it into thousands, hundreds, tens, and units and write each part with its symbols: 2024 is 2000 plus 20 plus 4, which is MM plus XX plus IV, so MMXXIV. To read a Roman numeral, add the symbol values (I is 1, V is 5, X is 10, L is 50, C is 100, D is 500, M is 1000) and subtract a smaller symbol placed before a larger one, so XLII is 42. Standard Roman numerals cover 1 to 3999 (the largest is MMMCMXCIX), a symbol repeats at most three times, and only IV, IX, XL, XC, CD, and CM may be subtracted. This converter runs entirely in your browser, works in both directions live, shows the breakdown, and rejects invalid forms like IIII and IC.
Converter Features
Why Use Roman Numeral Converter?
Both Directions, Live
Type a number to get its Roman numeral, or type a Roman numeral to get the number. The answer updates as you type, with no button to press.
Step-by-Step Breakdown
See exactly how a numeral is built, place by place. For example 2024 shows as MM plus XX plus IV, so you learn the pattern instead of just copying it.
Strict Validation
Bad numerals like IIII, VV, and IC are rejected with a plain reason and the correct form, so you never trust a wrong reading.
Full Reference Chart
The seven basic symbols and the six subtractive pairs are on the page, with a rules summary, so you can check any character at a glance.
Large Numbers Too
Standard numerals stop at 3999. Turn on the vinculum option to write larger values with an overline that multiplies a numeral by 1000, clearly labelled as non-standard.
100% In Your Browser
Every conversion runs on your device in JavaScript. Nothing you type is uploaded, logged, or sent to a server.
Common Uses for Roman Numerals
Dates and Years
Write copyright years, film release dates, and monument inscriptions in Roman numerals.
Clock and Watch Faces
Check the Roman numerals on a traditional dial, including the IIII versus IV convention.
Homework and Teaching
Learn the rules with a live breakdown and validation that explains why a numeral is wrong.
History and Reading
Decode numerals in book chapters, Super Bowl numbers, monarchs, and old manuscripts.
How It Works
Pick a direction
Choose Number to Roman to encode a value, or Roman to Number to decode a numeral. The Swap button flips between them.
Type your value
Enter a number from 1 to 3999, or a Roman numeral made of I, V, X, L, C, D, and M. The result appears instantly below the field.
Read the breakdown and copy
See the place-by-place breakdown that shows how the numeral is composed, then press Copy to put the result on your clipboard.
Tips and Rules
Read in Place Order
Split a number by thousands, hundreds, tens, and units before you write it. 1994 is 1000 plus 900 plus 90 plus 4, which is M plus CM plus XC plus IV, so MCMXCIV. The breakdown panel does this split for you.
Only Six Subtractive Pairs
The only valid subtractions are IV, IX, XL, XC, CD, and CM. If you find yourself writing IC, IL, or XM, you have gone wrong. The tool catches these and suggests the standard spelling.
Standard Stops at 3999
Plain Roman numerals only reach 3999 (MMMCMXCIX). For larger values, turn on the vinculum option, which draws a bar over a numeral to multiply it by 1000. It is clearly marked as non-standard.