Tool Fu
$ toolfu run roman-numeral-converter

Roman Numeral Converter — Convert Numbers to Roman Numerals Online Free

Convert numbers to Roman numerals and Roman numerals to numbers instantly. Free online Roman numeral converter for numbers 1–3999 — runs in your browser.

all processing runs in your browser
roman-numeral-converter
input > number (1–3999)
output > Roman numeral
MMXXIV
reference
I
1
V
5
X
10
L
50
C
100
D
500
M
1000

Free Online Roman Numeral Converter

Convert between decimal numbers and Roman numerals instantly. Supports numbers from 1 to 3999 with bidirectional conversion.

Features

  • Number to Roman numeral conversion
  • Roman numeral to number conversion
  • Instant swap between modes
  • Input validation for Roman numerals
  • Quick reference table
$ cat FAQ.md
What range of numbers can I convert?▶
Standard Roman numerals represent numbers from 1 to 3999. Numbers outside this range cannot be expressed in traditional Roman numeral notation.
How do Roman numerals work?▶
Roman numerals use combinations of letters (I=1, V=5, X=10, L=50, C=100, D=500, M=1000). Subtractive notation places a smaller value before a larger one to subtract (e.g., IV=4, IX=9).
Can I convert Roman numerals back to numbers?▶
Yes. Switch to 'Roman → Number' mode and enter a Roman numeral like MCMXCIV to get 1994.
Is the conversion case-sensitive?▶
No. You can enter Roman numerals in uppercase or lowercase — both work.