Free OnlineCalculators & Converters
Roman Numeral Converter
Convert between Roman numerals and Arabic numbers. Translate numbers to Roman numeral format and back instantly.
roman numeral converterroman numeralsconvert roman numbersroman to decimalnumber to roman
Reference Table
1I
4IV
5V
9IX
10X
40XL
50L
90XC
100C
400CD
500D
900CM
1000M
2024MMXXIV
2025MMXXV
2026MMXXVI
Key Features — Roman Numeral Converter
Arabic to Roman numeral conversion
Roman to Arabic number conversion
Validates Roman numeral correctness
Shows conversion rule breakdown
Supports numbers from 1 to 3,999,999
Why Use This Tool — Roman Numeral Converter
Free Online Roman numeral converterRoman numerals — for EveryoneFast & Easy Convert roman numbersRoman to decimal — 100% FreeFree Online Number to roman
Privacy First
All processing happens in your browser. Your data never leaves your device.
Lightning Fast
Get instant results with zero wait time. No server delays, no loading screens.
Works Everywhere
Use on any device — desktop, tablet, or phone. No downloads or plugins needed.
Frequently Asked Questions — Roman Numeral Converter
What are the basic Roman numeral symbols?
The seven basic symbols are I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). These are combined using additive and subtractive rules. For example, VI equals 6 (5+1) and IV equals 4 (5-1). Numbers up to 3,999 use standard notation.
What is the largest number that can be written in Roman numerals?
Standard Roman numerals go up to 3,999 (MMMCMXCIX). For larger numbers, a bar notation called vinculum places a line over a numeral to multiply it by 1,000. The tool supports extended notation for numbers beyond 3,999 up to 3,999,999.
How does the subtractive rule work?
A smaller numeral placed before a larger one is subtracted from it. IV means 5 minus 1, which equals 4. IX means 10 minus 1, which equals 9. XL means 50 minus 10, which equals 40. Only I, X, and C can be used subtractively and only before specific larger numerals.