Roman Numeral Converter
Convert numbers to Roman numerals or back, with a breakdown of each symbol.
Number to Roman Numeral
Roman Numeral to Number
Basic Roman Numerals
Roman Numeral Converter and Calculator
Roman numerals still appear on clocks, book pages and historical documents. Use this tool to turn a date or number into Roman numerals, or to read a string of I, V, X, L, C, D and M symbols as an ordinary number.
How Are Roman Numerals Written and Read?
Roman numerals rest on seven basic symbols: I (1), V (5), X (10), L (50), C (100), D (500) and M (1000). Written side by side, they form new numbers by adding or subtracting. A smaller symbol to the right of a larger one is added (VI = 6); one to the left is subtracted (IV = 4).
The Subtraction Principle and Writing Rules
A symbol can appear at most three times in a row. Numbers like 4 or 9 are written by subtraction. I can only be subtracted from V and X, X only from L and C, and C only from D and M.
Core Symbols
| Number | Roman Numeral |
|---|---|
| 1 | I |
| 4 | IV |
| 5 | V |
| 9 | IX |
| 10 | X |
| 40 | XL |
| 50 | L |
| 90 | XC |
| 100 | C |
| 400 | CD |
| 500 | D |
| 900 | CM |
| 1000 | M |
Roman Numeral Symbols and Values
Each letter has a fixed value: I=1, V=5, X=10, L=50, C=100, D=500 and M=1000. For larger numbers, a horizontal line is drawn over the letter, which multiplies its value by 1,000.
Roman Numeral Writing Rules
A smaller symbol placed to the right of a larger one: add.
A smaller symbol placed to the left of a larger one: subtract.
The same symbol may be written at most 3 times in a row.
Use IV for 4 and IX for 9. IIII is not valid.