Unit Converter

Free Roman Numeral Converter

Convert numbers (1 to 3999) to Roman numerals and back. See the symbol-by-symbol breakdown and copy the result in one click.

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Enter a number (1 – 3999)

Quick examples

Result

Converted value ROMAN

MMXXVI

2026 = MMXXVI

Symbol breakdown

How it works: Roman numerals use seven symbols — I (1), V (5), X (10), L (50), C (100), D (500), M (1000). Values are added left to right, except when a smaller symbol appears before a larger one, in which case it is subtracted. So IV = 4, IX = 9, XL = 40, and CM = 900.

About Roman Numerals

Roman numerals were the standard system of counting in the Roman Empire and remained in use across Europe well into the Middle Ages. They were gradually replaced by the Hindu–Arabic decimal system we use today, but they never disappeared entirely — you still see them on clock faces, in book chapter headings, movie sequels, monarch names (Elizabeth II), Super Bowl numbers (Super Bowl LVIII) and copyright dates on films and TV shows.

The seven symbols

Symbol	Value	Notes
I	1	One unit
V	5	Five — originally a hand shape
X	10	Ten — two V's joined
L	50	Fifty — half of 100
C	100	Centum (Latin for hundred)
D	500	Five hundred
M	1000	Mille (Latin for thousand)

The six subtractive pairs

The subtractive principle is the source of most of the confusion. In standard Roman numerals, only six subtractive combinations are allowed — anything else is non-standard:

Pair	Value	Why
IV	4	1 before 5
IX	9	1 before 10
XL	40	10 before 50
XC	90	10 before 100
CD	400	100 before 500
CM	900	100 before 1000

In ancient Rome, variants like IIII (for 4) and VIIII (for 9) were common — you can still see them on old clocks (particularly clocks made before the 20th century, and many contemporary clocks such as Big Ben). Modern standard notation requires the six subtractive pairs above.

Why the maximum is 3999

The standard Roman numeral system only has symbols for values up to M (1000). To represent 4000+ you would need either a new symbol (which the classical system did not have) or a special notation like an overline to mean "times 1000" — the V̅ notation. This tool uses the standard system, which tops out at MMMCMXCIX = 3999. The number 4000 would require a IV̅ with an overline, which is not part of standard notation.

Reading order

To read a Roman numeral, scan left to right. If a symbol is followed by one of equal or lesser value, add it. If a symbol is followed by one of greater value, subtract it. So MCMXCIV breaks down as M (1000) + CM (900) + XC (90) + IV (4) = 1994.

Common use cases

Copyright Dates

Convert MMXXV to 2025 for old film and TV copyrights.

Book Chapters

Convert chapter numbers between Arabic and Roman notation.

Monarch Numbers

Translate "Elizabeth II" (the second) or "Henry VIII" (the eighth).

Clock Faces

Read or repair traditional clock numerals.

Super Bowl Numbers

Convert Super Bowl LIX to Super Bowl 59.

Education

Learn or teach the Roman numeral system interactively.

Privacy and accuracy

This Roman numeral converter runs entirely in your browser. All conversion is done in pure JavaScript with no server calls. Nothing is uploaded, stored or logged.

Frequently Asked Questions

How do I convert a number to a Roman numeral?

Split the number into its place-value parts (thousands, hundreds, tens, units) and translate each part using the standard Roman symbols. For example, 1994 = 1000 (M) + 900 (CM) + 90 (XC) + 4 (IV), giving MCMXCIV.

What is the largest number that can be written in standard Roman numerals?

3999 = MMMCMXCIX. Beyond 3999, you need either a special overline notation (a bar over a numeral means "multiply by 1000") or the non-standard medieval symbols like ↁ (5000) and ↂ (10000), which are not part of the standard system. This tool follows the standard 1–3999 range.

Why is 4 written as IV instead of IIII?

Both are correct in different eras. The subtractive form IV is standard in modern notation, but ancient Romans commonly wrote IIII, and traditional clockmakers still use IIII on the 4 o'clock position (this is called the "watchmaker's four"). The reason is not fully known, but one common theory is aesthetic balance — IIII has four characters, matching the VIII on the opposite side of the clock face.

Can I use lowercase Roman numerals?

Yes, though it is non-standard. Lowercase is sometimes used for subtler pagination in printed books (i, ii, iii) or for stylistic effect. Standard usage is uppercase. This tool accepts either case on input and produces uppercase on output.

How do I read a Roman numeral like MMXXVI?

Scan from left to right, adding values unless a smaller symbol precedes a larger one. MMXXVI = M (1000) + M (1000) + X (10) + X (10) + V (5) + I (1) = 2026. There is no subtraction here because no smaller symbol is followed by a larger one.

What is the difference between IIX and VIII?

VIII is the standard Roman numeral for 8 (5 + 1 + 1 + 1). IIX is a non-standard variant (10 − 1 − 1 = 8) that appears on a few historic clock faces, particularly the famous astronomical clock in Prague. Modern usage is VIII; IIX is considered archaic.

Is this Roman numeral converter free?

Yes. It is 100% free, requires no sign-up, and runs entirely in your browser.

Is my input sent to a server?

No. All conversions happen locally in JavaScript. Nothing is uploaded, stored or logged.

Does the tool accept lowercase input?

Yes. The input is normalised to uppercase before conversion, so typing mcmxciv produces the same result as typing MCMXCIV.

What happens if I enter an invalid Roman numeral?

The tool shows a clear error message explaining what is wrong — for example, "IIII is not standard; use IV for 4" or "Symbols must be in descending order except for the six subtractive pairs". The result panel is hidden until a valid input is entered.