Roman Numerals to Numbers

Enter a Roman numeral and convert it to a standard number. Results appear instantly in your browser.

Roman Numeral
Valid symbols: I V X L C D M
Number
Result will appear here
Quick Reference
I→1
V→5
X→10
L→50
C→100
D→500
M→1000
IV→4
IX→9
XL→40
XC→90
CD→400
CM→900

Roman Numerals to Numbers Converter

This tool converts Roman numeral strings into their standard number (integer) equivalents. It validates the input and reports errors for invalid Roman numeral sequences.

The conversion runs entirely in your browser. Enter a valid Roman numeral using the letters I, V, X, L, C, D, and M.

How to use

  1. Type or paste a Roman numeral into the input field (e.g. XIV or MCMXCIX).
  2. Click Convert to see the number result.
  3. Use Copy to copy the number to your clipboard.
  4. Click Clear to reset.

How it works

The tool reads the Roman numeral from left to right. It maps each letter to its value (I=1, V=5, X=10, L=50, C=100, D=500, M=1000). If a smaller value appears before a larger value, it is subtracted (e.g. IV = 4, IX = 9). Otherwise, values are added together.

Example

Roman: XIV
Number: 14

Roman: MCMXCIX
Number: 1999

Roman: MMXXVI
Number: 2026