Roman Numeral Converter
Convert numbers to Roman numerals and vice versa. Supports standard Roman numerals up to 3999 and extended notation.
Roman Numeral Chart
I = 1
IV = 4
V = 5
IX = 9
X = 10
XL = 40
L = 50
XC = 90
C = 100
CD = 400
D = 500
CM = 900
M = 1000
About this calculator
Convert numbers to Roman numerals and Roman numerals to numbers, with a breakdown that shows each symbol's value: for 2026, M + M + X + X + V + I. The chart of symbols and subtractive pairs is on the page.
Useful for students, designers and anyone decoding dates on buildings and monuments.
How to use it
- Press Number → Roman and enter a number from 1 to 3,999.
- Or press Roman → Number and enter a numeral.
- Read the result and the breakdown.
Rules
Add symbols from largest to smallest and subtract when a smaller symbol precedes a larger one (IV, IX, XL, XC, CD, CM). No symbol repeats more than three times in a row.
Worked example
2026
| Roman numeral | MMXXVI |
| Breakdown | M (1000) + M (1000) + X (10) + X (10) + V (5) + I (1) |
Tips and common mistakes
- Start with thousands and work down.
- Subtractive pairs: IV, IX, XL, XC, CD, CM.
- Read Roman numerals left to right, adding unless a smaller precedes a larger.
- Years are common: MCMXCIX is 1999.
- Lowercase numerals are used for page numbers in prefaces.
Frequently asked questions
How do I read Roman numerals?
Add the values, subtracting when a smaller symbol comes before a larger one.
What is XL?
40.
What is MCMXCIV?
1994.
Can numerals be repeated?
Up to three times.
What is the biggest standard numeral?
3,999.
How do I write 2026?
MMXXVI.