Roman Numeral Converter — Number to Roman Numerals Online Free
Convert Arabic numbers to Roman numerals and back. Supports 1–3999 with symbol breakdown, reference table, and copy buttons — all in your browser.
Also searched as: roman numeral converter · number to roman numerals · roman numerals translator · convert to roman numerals online
Arabic → Roman
MMXXVI
Breakdown
Roman → Arabic
2026
Quick reference
| Symbol | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1000 |
| Subtractive pairs | |
|---|---|
| IV | 4 |
| IX | 9 |
| XL | 40 |
| XC | 90 |
| CD | 400 |
| CM | 900 |
Did you know?
- Traditional Roman numerals are most often used for values from 1 to 3999.
- Rome is traditionally dated to 753 BC — written in Roman numerals as DCCLIII.
- The current year 2026 is MMXXVI in Roman numerals.
How to Use
Step-by-step guide to get the most from this tool
- 1
Arabic to Roman
Enter a number from 1 to 3999 on the left to see the Roman equivalent and breakdown.
- 2
Roman to Arabic
Type a Roman numeral on the right to decode it to a decimal number.
- 3
Use the reference
Check the symbol table and subtractive pairs for quick lookups.
- 4
Copy results
Use the copy buttons beside each output to paste elsewhere.
Features
What makes this tool stand out
Bidirectional
Convert Arabic ↔ Roman instantly.
Breakdown
See how each Roman symbol builds the number.
Reference table
Basic symbols and subtractive pairs.
One-click copy
Copy Roman or Arabic output.
Shareable
Encode inputs in a shareable URL.
Offline-ready
Pure client-side logic — no server.
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Frequently Asked Questions
Quick answers to common questions
What range of numbers are supported?+
Standard Roman numerals from 1 to 3999. This matches classical notation without vinculum (overline) extensions for larger values.
How does subtractive notation work?+
A smaller symbol before a larger one is subtracted — for example, IV is 4 (5 − 1) and CM is 900 (1000 − 100).
Why is my Roman input invalid?+
Only combinations that follow classical rules are accepted — no more than three identical symbols in a row, and only standard subtractive pairs like IV, IX, XL, XC, CD, and CM.
What is the breakdown panel?+
When converting Arabic to Roman, the breakdown shows each symbol chunk used to build the result, such as M=1000 and CM=900.
Is my data private?+
Yes. All conversion runs entirely in your browser with no network requests.