Roman Numeral Converter
Convert between Roman numerals and standard numbers instantly. Supports numbers from 1 to 3,999. Includes a complete Roman numeral reference chart. Free and private — runs in your browser.
Roman Numeral Reference Chart
| Roman | Number | Roman | Number |
|---|---|---|---|
| I | 1 | C | 100 |
| IV | 4 | CD | 400 |
| V | 5 | D | 500 |
| IX | 9 | CM | 900 |
| X | 10 | M | 1000 |
| XL | 40 | MMXXVI | 2026 |
| L | 50 | MMMCMXCIX | 3999 |
| XC | 90 |
How Roman Numeral Conversion Works
Roman numerals use seven symbols: I (1), V (5), X (10), L (50), C (100), D (500), and M (1000). Numbers are formed by combining these symbols and adding their values. When a smaller numeral appears before a larger one, it is subtracted (e.g., IV = 4, IX = 9).
Roman Numeral Rules
Addition: VI = 5 + 1 = 6, XII = 10 + 1 + 1 = 12
Subtraction: IV = 5 − 1 = 4, XC = 100 − 10 = 90
Maximum: The largest standard Roman numeral is MMMCMXCIX = 3999
Common Uses of Roman Numerals
Roman numerals are used in clock faces, book chapters, movie sequels (Star Wars Episode IV), Super Bowl numbering (Super Bowl LVIII), building cornerstones, outlines, and copyright dates on films and TV shows. Understanding Roman numerals helps you read dates on historic buildings and monuments.
Roman Numeral Converter for Students
Students often need to convert Roman numerals for math homework, history assignments, and standardized tests. This free converter handles both directions — enter a number to get the Roman numeral, or enter a Roman numeral to get the decimal value. It supports all valid combinations from I (1) to MMMCMXCIX (3999).
Common Conversion Tips
Always verify the source and target units or formats before converting — selecting the wrong option is the most common mistake. For precise conversions, enter values with as many decimal places as you have available. If converting multiple items, work through them one at a time to avoid mixing up results. Bookmark this page for quick access when you need to convert again in the future.
Frequently Asked Questions
What is the largest Roman numeral?
The largest standard Roman numeral is MMMCMXCIX, which equals 3,999. Numbers above 3,999 require non-standard notation with overlines (vinculum) to indicate multiplication by 1,000.
Why is 4 written as IV instead of IIII?
Roman numerals use subtractive notation where a smaller value before a larger one means subtraction: IV = 5 − 1 = 4. This keeps numbers shorter. However, some clock faces use IIII for 4 by tradition.
Is there a Roman numeral for zero?
No. The Roman numeral system has no symbol for zero. It was developed before the concept of zero was widely adopted in Western mathematics. The word "nulla" (meaning nothing) was sometimes used instead.
How do you read Roman numerals?
Read left to right. If a smaller numeral appears before a larger one, subtract it (IV = 4). Otherwise, add all values: XVII = 10 + 5 + 1 + 1 = 17.
What year is MMXXVI in Roman numerals?
MMXXVI = 2026. M=1000, M=1000, X=10, X=10, V=5, I=1. Total: 1000+1000+10+10+5+1 = 2026.