Roman Numeral Converter
Number to Roman Numeral
Roman Numeral to Number
Roman Numeral Reference
I
1
V
5
X
10
L
50
C
100
D
500
M
1000
Free Online Roman Numeral Converter
Our free Roman numeral converter lets you instantly convert integers to Roman numerals and Roman numerals back to decimal numbers. It supports all values from 1 to 3999 (the standard range of Roman numerals) and validates your input in real time. Whether you need to read dates on buildings, convert chapter numbers, or solve homework problems, this tool makes the process quick and effortless.
How to Use
To convert a number to a Roman numeral, type a whole number between 1 and 3999 into the left input field. The Roman numeral equivalent will appear instantly below. To convert a Roman numeral to a number, type valid Roman numeral characters (I, V, X, L, C, D, M) into the right input field and the decimal value will appear below. Both conversions happen in real time as you type.
FAQ
What is the largest number you can write in Roman numerals?
Using the standard set of Roman numeral symbols (I, V, X, L, C, D, M), the largest number that can be represented is 3999, written as MMMCMXCIX. Numbers beyond 3999 historically required special notations such as a bar (vinculum) placed above numerals to multiply their value by 1000.
Is there a Roman numeral for zero?
No. The Roman numeral system does not have a symbol for zero. The concept of zero as a number was introduced later through the Hindu-Arabic numeral system.
What are the basic rules of Roman numerals?
Roman numerals are generally written from largest to smallest, left to right. When a smaller numeral appears before a larger one, it is subtracted (e.g., IV = 4, IX = 9). A numeral can be repeated up to three times in succession (e.g., III = 3), but V, L, and D are never repeated.