Roman Numerals to Number

Read any Roman numeral

Roman numerals use seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1,000. You add values from left to right, except when a smaller numeral comes before a larger one, which means subtract it: IV is 4, IX is 9, XL is 40 and CM is 900.

Enter any Roman numeral and the converter gives you the number. For example, MMXXVI is 2026 and MCMXCIX is 1999.

You'll still see Roman numerals on clock faces, building cornerstones, film copyright dates, book chapters, outlines, monarchs' names, Super Bowls and tattoos.

How to use the roman numerals to number

1. Type the Roman numerals.
2. Submit to convert.
3. Read the resulting number.

Examples

This year

Input: MMXXVI

Output: 2026

Subtractive pairs

Input: MCMXCIV

Output: 1994

M (1000) + CM (900) + XC (90) + IV (4).

The largest standard numeral

Input: MMMCMXCIX

Output: 3999

Clock-face style

Input: IIII

Output: 4

Accepted even though IV is the standard form.

Common uses

• Reading years in movie credits and on buildings.
• Understanding chapter and volume numbers.
• Checking dates for Roman numeral tattoos.
• Homework on number systems.
• Reading names like Louis XIV or Super Bowl LX.
• Reading copyright years at the end of films and TV shows.
• Understanding chapter, volume and appendix numbers in books.
• Checking dates on monuments, cornerstones and clock faces.
• Reading names of monarchs, popes and events like Super Bowl LX.

Tips and things to know

• Only I, X and C are used for subtraction, and only before the next two higher values (I before V and X, X before L and C, C before D and M).
• A numeral is never repeated more than three times in a row in standard form: 4 is IV, not IIII (though some clocks use IIII).
• Standard numerals go up to 3,999 (MMMCMXCIX). Larger numbers used special overline notation.
• To spell the result out, use the number to words converter.

Edge cases and limitations

• Use capital letters. Lowercase mmxxvi gives 0.
• Reading stops quietly at the first character it can't use. MMXZ returns 2010 instead of an error, so double-check typos.
• Non-standard combinations aren't rejected: VX returns 5 and IC returns 1, because the parser reads from left to right and stops when the order breaks.
• Spaces inside the numeral stop the reading at the space.

Frequently asked questions

What is 2026 in Roman numerals?

MMXXVI.

Why is 4 written IV?

Placing I before V means 5 minus 1. This subtractive notation keeps numerals short.

Is there a zero in Roman numerals?

No. The Roman system has no symbol for zero.

What does MCMXC mean?

1990: M (1000) + CM (900) + XC (90).

How are numbers above 3,999 written?

Traditionally with a bar over a numeral, which multiplies it by 1,000. There's no standard way to type that, so this tool handles values up to MMMCMXCIX (3,999).

Can I convert a number into Roman numerals?

This tool works in one direction, from Roman numerals to numbers. To write 2026 the other way, build it from the largest values down: MM (2000) + XX (20) + VI (6) = MMXXVI.

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