Roman Numeral Converter — Arabic ↔ Roman Both Ways (Free, Instant)

How to use

Enter a number (1–3999) or Roman numeral.
Press Convert — the other form appears with breakdown.
Use the reference table below for study.

About this tool

Roman numerals appear in clocks, movie credits, chapters and monarch names. This converter handles both directions with proper subtractive notation (IV, IX, XL, CM), validates input strictly, and shows the additive breakdown so students see why 1994 = MCMXCIV. Local and instant, like all our tools. Your file never leaves this page — everything runs in your browser, there is no upload endpoint on this site, and the file is dropped from memory when you close the tab.

FAQ

Range?

1–3999 — classical Roman numerals have no zero and standard notation stops at 3999.

Why no 4000+?

Ancient notation used overlines for thousands-multipliers; we stick to the standard classroom form.

Lowercase input?

Accepted and normalized to uppercase.

Is 'IIII' valid?

No — subtractive form requires IV; clock faces use IIII as tradition, not maths.

Can I copy results?

One click.

How does the breakdown work?

Each digit maps to its place-value symbol group (900=CM, 40=XL…).

Rate this tool

Your rating stays in this browser (local storage) — nothing is sent to any server.

Questions people ask about Roman Numeral Converter

Collected from live search results on 04 Sep 2026 (search-engine "people also ask" boxes plus the questions published on ranking pages).

What is "I love you" in Roman numerals?