Roman Numeral Converter
Convert between Roman numerals and numbers, either direction. Supports the standard range 1–3999 with strict subtractive-notation validation. Runs entirely in your browser.
Direction
Try
Symbols
- I
- 1
- V
- 5
- X
- 10
- L
- 50
- C
- 100
- D
- 500
- M
- 1000
Rules
- Symbols add when a larger or equal value precedes a smaller one — VI = 5 + 1 = 6.
- A smaller symbol before a larger one subtracts — IV = 5 − 1 = 4, CM = 1000 − 100 = 900.
- Only I, X, and C can precede a larger symbol. The same letter repeats at most three times in a row, so 4 is IV, not IIII.
- Standard range is 1–3999.
Frequently asked questions
How do I write a year like 2024 in Roman numerals?
2024 is MMXXIV — that is 1000 + 1000 + 10 + 10 + (5 − 1). Enter the number and the converter shows the numeral plus a symbol-by- symbol breakdown.
What range of numbers is supported?
The standard range 1–3999. Classic Roman numerals have no symbol for zero or negatives, and values of 4000 and above need overbar notation that this tool does not use.
Why is IIII rejected for 4?
The converter enforces strict subtractive notation, so a symbol repeats at most three times and 4 must be written IV, 9 as IX, and 40 as XL.
Can it convert Roman numerals back to numbers?
Yes. Switch the direction toggle to Roman → Number, type a numeral such as MCMXCIV, and it returns 1994.
Related tools
- Coin Flip Flip a virtual coin with a satisfying animation and outcome history.
- Dice Roller Roll D4, D6, D8, D10, D12, or D20 dice for games and decisions.
- Binary / Hex Converter Convert numbers between binary, hex, decimal, and octal in one tool.
- Percentage Calculator Compute percentages, increases, decreases, and percentage-of values.