Convert numbers to Roman numerals and Roman numerals back to decimal. Supports 1 to 3,999,999.
Symbols placed left to right are added: VIII = 5+1+1+1 = 8, XII = 10+1+1 = 12.
A smaller symbol before a larger is subtracted: IV = 5−1 = 4, XL = 50−10 = 40.
I, X, C, M can repeat up to 3 times. V, L, D cannot repeat. Use subtractive form instead.
Roman numerals are a numeric system originating in ancient Rome, using combinations of seven Latin letters - I (1), V (5), X (10), L (50), C (100), D (500), and M (1000) - to represent numbers. Developed around 900-800 BCE and refined over subsequent centuries, this system dominated European arithmetic for over a millennium before the Hindu-Arabic numeral system gradually replaced it. Ironically, the positional decimal system that displaced Roman numerals was largely transmitted to Europe through medieval Arab scholars who had learned it from Indian mathematicians.
India's contribution to the numeral system we use today is profound - Aryabhata (476 CE) and Brahmagupta (628 CE) formalised decimal place value and the concept of zero, which eventually made Roman numerals obsolete for calculation. Yet Roman numerals persist widely today: CBSE and ICSE mark exam chapters in Roman numerals, Indian courts number their sections as I, II, III, the Indian Constitution's articles use them, and film copyright notices display production years in Roman form. Clock faces, Super Bowl numbering, and building cornerstones also still use the system.
This tool handles both directions: Arabic to Roman and Roman to Arabic. It supports numbers from 1 to 3,999,999 using standard subtractive notation (IV=4, IX=9, XL=40, XC=90, CD=400, CM=900) plus overline extension for thousands. Enter a number or Roman string and get an instant result.