Roman Numerals Chart and Converter Guide (1–3999)

Roman numerals still show up on clocks, outlines, monuments, and exam papers. Modern math uses Arabic digits (1, 2, 3…), but converting between systems is a recurring homework and design task.

A Roman numeral converter maps integers 1–3999 to strings like XIV and decodes MMXXVI back to 2026. This guide explains the rules, provides a quick chart, and links to Toolsle’s free Roman numeral converter.

The seven symbols

Most values combine symbols left to right, adding as you go: VI = 6, XV = 15.

Subtractive notation (why IV = 4)

Place a smaller symbol before a larger one to subtract:

This keeps strings short—IV instead of IIII (though clocks sometimes use IIII on dials for tradition).

Classic rule: Only subtract I from V or X, X from L or C, and C from D or M. Do not repeat subtractive pairs ad infinitum.

Quick reference chart

How conversion algorithms work

Arabic → Roman: Walk a table from largest to smallest (1000, 900, 500, 400, …). While the remainder fits, append the symbol and subtract.

Roman → Arabic: Scan left to right. If the next symbol is larger, subtract the current and skip ahead; otherwise add.

Invalid strings (like IIV) should be rejected—good tools flag malformed input instead of guessing.

Common uses today

• Chapter and outline numbering in documents
• Clock faces (often IIII for 4)
• Copyright years on films (© MMXXVI)
• Super Bowl / event branding (e.g. LVIII)
• Education — Latin classes and math puzzles

For spelling numbers in words, use our number to words tool; for other bases, try hex to decimal.

Mistakes students make

• Writing 4000+ — classical Roman form in schools stops at 3999 (MMMCMXCIX)
• Repeating V, L, or D (VII is invalid—use VI + I patterns correctly)
• Forgetting subtractive pairs on exams (90 is XC, not LXXXX)

Try the free Roman numeral converter

Type in either field on the Roman numeral converter—Arabic or Roman—and the other updates live in your browser.