Utilore

Roman Numerals

A year on a monument, a chapter number, a clock face, a tattoo you would rather get right. Type digits and get letters, or letters and get digits.

Type 2026 to get MMXXVI, or MMXXVI to get 2026 — the direction follows what you type.

How it is built

Both directions are strict: a numeral is accepted only if it is written the way the rules require, so a typo comes back as an error instead of a plausible wrong number.

How to use

  1. Type a number, like 2026, or a Roman numeral, like MMXXVI.
  2. Read the answer — the direction is chosen from what you typed.
  3. Look at the breakdown below to see which letters carry which value.

Good to know

Why four is IV and not IIII

Roman notation avoids four identical letters in a row by writing the smaller symbol before the larger one: IV is «one before five», XL is «ten before fifty». Clock faces often show IIII anyway — a habit, not a rule — which is exactly why a converter has to pick one and be strict about it.

Where the system ends

There is no zero and no minus: the notation grew out of counting things, and nobody counted nothing. The upper limit is 3999, because 4000 would need four Ms in a row. Beyond that classical writing puts a bar over a letter to multiply it by a thousand — a form with no single agreed way to type it.

Frequently asked questions

Why is IIII rejected?

Because it is not how the number is written. A converter that quietly accepted it would also accept a typo and hand back a plausible wrong answer — worse than saying no.

What is the largest number I can convert?

3999, written MMMCMXCIX. Above that you need the overline notation, which has no single form and no reliable way to display everywhere.

Can I convert a year of birth?

Yes, any year from 1 to 3999. 1994 is MCMXCIV, 2026 is MMXXVI.

Is anything sent to a server?

No. The conversion is arithmetic done in your browser; the page works with the network switched off.

Related tools