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Roman Numeral Converter – Numbers to Roman Numerals and Back

Convert any number from 1 to 3,999 into Roman numerals, or type Roman numerals to turn them back into a number. The converter detects which way you’re going and shows how the numeral is built up from thousands, hundreds, tens and ones.

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How to use the Roman numeral converter

Type either:

  • a number from 1 to 3,999 (commas are fine), to get the Roman numeral, or
  • a Roman numeral such as MCMXCIV (upper or lower case), to get the number.

The converter works out which way to convert, shows the result and breaks it down place by place. Invalid numerals such as IIII or VX are rejected with a suggestion.

The symbols

SymbolValue
I1
V5
X10
L50
C100
D500
M1,000

The rules

  1. Add symbols written from largest to smallest: VI = 5 + 1 = 6, LX = 60.
  2. Subtract a smaller symbol placed before a larger one, using only IV, IX, XL, XC, CD and CM.
  3. Repeat I, X, C and M at most three times in a row; never repeat V, L or D.
  4. Build numbers place by place: thousands, then hundreds, then tens, then ones.

Worked examples

  • 1994 = 1000 + 900 + 90 + 4 = M + CM + XC + IV = MCMXCIV
  • 2026 = 2000 + 20 + 6 = MM + XX + VI = MMXXVI
  • 3,999 = MMM + CM + XC + IX = MMMCMXCIX
  • XLII = XL (40) + II (2) = 42
  • CDXLIV = CD (400) + XL (40) + IV (4) = 444

Where Roman numerals are used today

  • Years on film credits, building foundation stones and copyright lines (MMXXVI).
  • Clocks and watches, often with IIII instead of IV.
  • Monarchs and popes: Elizabeth II, Louis XIV, Benedict XVI.
  • Book chapters, outlines and prefaces, often in lower case (i, ii, iii).
  • Sporting events: the Super Bowl and Olympic Games are numbered with Roman numerals.
  • Tattoos and jewellery with birth years or anniversaries — double-check the conversion before making it permanent.

A little history

Roman numerals developed in ancient Rome from tally marks and stayed the usual way to write numbers in Europe until the late Middle Ages. Hindu-Arabic numerals — the digits 0 to 9 we use today — gradually replaced them because place value and the zero make arithmetic much easier. Try multiplying XLVII by XIX in Roman numerals and the advantage is obvious. Roman numerals survive today mainly for decoration, tradition and numbering.

Some modern uses still follow the rules loosely, so check the exact form if you need it to be correct.

Tips for reading long numerals

Split the numeral at each change of place value. MDCCCLXXXVIII → M · DCCC · LXXX · VIII = 1000 + 800 + 80 + 8 = 1888. Reading left to right, if a symbol is smaller than the one after it, subtract it; otherwise add it.

To write numbers in words — for cheques or invoices — use number to words. To convert between binary, hex and decimal, try the number base converter.

Frequently asked questions

What is 2026 in Roman numerals?

MMXXVI: MM = 2,000, XX = 20 and VI = 6.

What are the seven Roman numeral symbols?

I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000.

How does subtraction work in Roman numerals?

A smaller symbol before a larger one is subtracted. Only six pairs are used: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900). So 1994 is MCMXCIV: M + CM + XC + IV.

Why does the converter stop at 3,999?

Standard Roman numerals have no symbol above M (1,000) and don’t repeat a symbol more than three times, so MMMCMXCIX (3,999) is the largest. Larger numbers used a bar over a numeral to multiply it by 1,000, which isn’t standard today.

Is IIII correct for 4?

The standard form is IV, and the converter accepts only standard forms. You may see IIII on clock faces, which is a long-standing design tradition.

Is there a Roman numeral for zero?

No. The Romans had no symbol for zero; medieval writers sometimes used the word nulla.

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