Roman numeral converter

Numbers to Roman numerals and back, with each place value explained.

Formula Maths

Roman numeral

Breakdown: MM (2000) + XX (20) + VI (6)

How it works

Roman numerals use I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1000. Each place value (thousands, hundreds, tens, units) is written separately and joined.

A smaller symbol before a larger one is subtracted, but only in six pairs: IV, IX, XL, XC, CD and CM. No symbol repeats more than three times, which is why standard numerals stop at 3999.

Formula

I 1 · V 5 · X 10 · L 50 · C 100 · D 500 · M 1000
IV 4 · IX 9 · XL 40 · XC 90 · CD 400 · CM 900

Worked example

2026 = MM (2000) + XX (20) + VI (6) = MMXXVI. MCMLXXXIV = 1000 + 900 + 80 + 4 = 1984.

Questions people ask

Why do some clocks show IIII instead of IV?

It is a long clock-making tradition, often said to balance the dial visually. In standard modern form 4 is written IV.

Is there a Roman numeral for zero?

No. The Roman system had no symbol for zero; the word nulla was sometimes used instead.

How are numbers above 3999 written?

With a bar over a numeral, meaning times 1000: V with a bar is 5000. That form is not standardised, so this converter stops at 3999.