Roman Numeral Converter
Convert a number to a Roman numeral, or convert a Roman numeral back to a number.
| Number (1–3999) |
| Roman numeral |
Result
Your conversion will appear here.
Symbols and rules
I=1, V=5, X=10, L=50, C=100, D=500, M=1000
Symbols are usually written largest to smallest and added together (e.g. VI = 5+1 = 6, XX = 20). A smaller symbol placed before a larger one is subtracted (e.g. IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900).
Notes
This converter supports the standard range 1 to 3999. There is no zero in Roman numerals, and historical writing varied; this tool uses the common modern subtractive form. (Values above 3999 were sometimes written with an overline/vinculum to multiply by 1,000, which this simple converter does not produce.)
How it works
Roman numerals use letters with fixed values (I=1, V=5, X=10, L=50, C=100, D=500, M=1000). Standard form writes symbols largest to smallest, except subtractive pairs (IV=4, IX=9, XL=40, XC=90, CD=400, CM=900).
Rules and examples
- Add values when a smaller or equal symbol follows (VI=6). Subtract when a smaller precedes a larger in allowed pairs (IX=9).
- Standard range shown here is 1–3999 (I to MMMCMXCIX).
Worked example
2026 = 2000 + 20 + 6 = MM + XX + VI = MMXXVI.
For general information and learning. Historical notation can vary outside standard modern form.
How to use the Roman Numeral Converter
It takes a few seconds, and every figure is calculated in your browser.
- Enter a number from 1 to 3999.
- Enter the roman numeral.
- Press Calculate — the result appears in the dark panel beside the form.
- Use Copy, CSV, Share or Print under the result if you want to keep it.
Roman Numeral Converter — frequently asked questions
How does the Roman Numeral Converter work?
Roman numerals use letters with fixed values (I=1, V=5, X=10, L=50, C=100, D=500, M=1000). Standard form writes symbols largest to smallest, except subtractive pairs (IV=4, IX=9, XL=40, XC=90, CD=400, CM=900).
What assumptions and limitations should I know about?
This converter supports the standard range 1 to 3999. There is no zero in Roman numerals, and historical writing varied; this tool uses the common modern subtractive form. (Values above 3999 were sometimes written with an overline/vinculum to multiply by 1,000, which this simple converter does not produce.)
Can you walk through a worked example?
Add values when a smaller or equal symbol follows (VI=6). Subtract when a smaller precedes a larger in allowed pairs (IX=9). Standard range shown here is 1–3999 (I to MMMCMXCIX).
Last updated 10 November 2026 · Formula, worked example and assumptions are documented above, and every result is calculated in your browser.