Roman Numeral Converter

Converts numbers to Roman numerals and back, and shows how each one is built, for example 1994 = M + CM + XC + IV. Use it to read years and chapter numbers or to write a date in Roman numerals.

How to use

1. Enter a number from 1 to 3,999 in "Number", or a numeral such as XIV in "Roman numeral". The other box updates at once; upper and lower case both work.
2. "How it is built" shows the symbols for each place and where one is subtracted. "Output letters" switches between letters, Unicode numerals and lower case.
3. For 4,000 and above, switch on the option for a line over the letters to convert numbers up to 3,999,999.
4. On the "Date" tab, pick a date, an "Order" and a "Separator" to get the date in Roman numerals. The "Tables" tab has a printable chart from 1 to 100.

How it works

• I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. Symbols are written from largest to smallest and added; a smaller one before a larger one is subtracted (IV, IX, XL, XC, CD, CM).
• For a non-standard form such as IIII or VX, the tool explains the broken rule and shows the standard form.
• Zero and negative numbers cannot be written in Roman numerals. A line over a letter multiplies it by 1,000 and is used from 4,000 upward.

Questions and answers

Is 4 in Roman numerals IV or IIII?

The standard form is IV, because a symbol is repeated at most three times. Clock faces often show IIII as an old design tradition.

What number is XIV?

14. X is 10, and IV is 5 − 1 = 4.

How do you write 2026 in Roman numerals?

MMXXVI: 2000 is MM, 20 is XX and 6 is VI, written one after the other.

What is the largest Roman numeral?

With the standard symbols it is 3999 (MMMCMXCIX). Larger numbers are written with a line over the letters, which multiplies them by 1,000.