Roman Numeral Converter
Convert numbers to Roman numerals and back, with each step shown. Flags non-standard forms such as IIII and supports overlines to 3,999,999.
Roman numeral letters
| Letter | Value |
|---|---|
| I | 1 |
| V | 5 |
| X | 10 |
| L | 50 |
| C | 100 |
| D | 500 |
| M | 1,000 |
Shortcuts: Ctrl+Enter run · Ctrl+Shift+C copy result · / search (use ⌘ on Mac)
Free Roman Numeral Converter
Type a number or a Roman numeral and get the other one. The steps show how the answer is built, and unusual spellings are pointed out. It gives developers a quick browser-based way to solve a focused roman numeral converter task before moving the result into a project.
How to use Roman Numeral Converter
Type a number such as 1994 or a Roman numeral such as MCMXCIV. Turn on "overlines" to write numbers above 3,999.
Common mistakes
- Entering 0 or a negative number: Roman numerals start at 1.
- Using a letter that is not I, V, X, L, C, D or M: the page names the position of the wrong letter.
Frequently asked questions
Why does Roman numeral conversion stop at 3,999?
The usual system has no letter above M (1,000) and repeats a letter at most three times, so 3,999 (MMMCMXCIX) is the largest. A bar over a letter multiplies it by 1,000 and reaches 3,999,999.
Is IIII a wrong Roman numeral?
It is not the standard form, which is IV, but you see IIII on many clocks. The page reads it and tells you the standard spelling.
Is there a Roman numeral for zero?
No. The Romans had no zero. Numbers start at 1 (I).
Is anything uploaded?
No. The conversion runs in your browser.
How do I use this roman numeral converter tool?
Use the interactive controls above; processing stays in your browser and the result is intended as a practical starting point for development work.
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