Roman Numeral Converter

About Roman Numerals

Roman numerals are a numeral system that originated in ancient Rome and remained the usual way of writing numbers throughout Europe well into the Late Middle Ages. Unlike the decimal system, which uses place value (ones, tens, hundreds), Roman numerals build every number from combinations of seven fixed-value letters.

Key Symbols and Landmark Values

These seven letters are all you need. Every other Roman numeral is a combination of them.

A few landmark values worth memorizing, since they come up constantly in dates, event numbering, and copyright years:

Roman Numerals Chart: 1 to 100

The full chart below lists every number from 1 to 100 with its Roman numeral. It is generated directly from the same conversion logic as the tool above, so it always matches.

How to Use the Converter

1. Choose the conversion direction - "Number to Roman" or "Roman to Number"
2. Enter your input - Type a number (1-3999) or a Roman numeral
3. Click the Convert button - See your result instantly
4. Copy the result - Use the copy button to easily copy the converted value

How Roman Numerals Work

Every Roman numeral is built from the seven symbols above using two principles.

The additive principle: when a symbol appears after a symbol of equal or greater value, add it. VI is V (5) followed by I (1), so it reads as 6. XV is X (10) followed by V (5), so it reads as 15.

The subtractive principle: when a smaller symbol appears immediately before a larger one, subtract it. IV is I (1) before V (5), so it reads as 4. Subtraction is deliberately limited: only I, X, and C are ever used as the subtracted symbol, and each one can only be subtracted from the next two higher symbols. I can only come before V or X (IV, IX). X can only come before L or C (XL, XC). C can only come before D or M (CD, CM). You will never see IL for 49 or IC for 99, those are decomposed instead as XLIX and XCIX.

The repetition rule: a symbol is never repeated more than three times in a row. III is 3, but 4 is not IIII, it is IV. XXX is 30, but 40 is not XXXX, it is XL. This is also why 4 is written IV rather than the more literal-looking IIII, with one notable exception: many analog clock faces still use IIII for the 4 position, mostly for visual balance against the VIII on the other side of the dial, and because that was the traditional form used by clockmakers.

There is no symbol for zero. The Romans built their number system for counting and measuring quantities that were actually present, and the concept of zero as a number in its own right was not introduced into Western mathematics until centuries later, through the Hindu-Arabic numeral system.

Worked Example: Converting 1994 to Roman Numerals

Decomposing a number into Roman numerals is easiest working from the largest value down, repeatedly subtracting the biggest symbol or pair that still fits.

1. 1994 is at least 1000, so take M and subtract 1000: 994 left
2. 994 is at least 900, so take CM and subtract 900: 94 left
3. 94 is at least 90, so take XC and subtract 90: 4 left
4. 4 is exactly IV, subtract 4: 0 left
5. Combine the pieces in order: M + CM + XC + IV = MCMXCIV

A shorter example: 49 breaks down as 40 + 9, which is XL + IX, giving XLIX. The same method works for any number up to 3999, and it is exactly what the converter above does automatically.

Dates in Roman numerals

A date is the usual reason people need Roman numerals, for a tattoo, a ring or a wedding invitation. The Date to Roman tab converts the day, month and year together, and lets you pick the order and the separator between them.

The 3,999 Limit and Larger Numbers

With only the seven standard symbols and the "no more than three in a row" rule, the largest number you can write is MMMCMXCIX, which is 3999. There is no standard basic symbol larger than M (1000), so you cannot go higher without extending the system. Every whole number from 1 to 1000, and up through 3999, is fully covered by the standard symbols; the limit only becomes relevant above 3999.

Historically, Romans extended the system for larger numbers with a vinculum, a bar drawn over a numeral that multiplied its value by 1000. A V with a bar over it meant 5,000, and an M with a bar over it meant 1,000,000. This notation was never fully standardized and is rarely seen outside historical texts, but the converter above supports it, so numbers up to 3,999,999 come out as M\u0305 and the like.

Dates in Roman Numerals

Writing a full date in Roman numerals is one of the most common reasons people search for a converter like this one, usually for a birthday, wedding anniversary, or tattoo. The idea is simple: convert the day, month, and year separately, then join them with dots, slashes, or dashes. July 4, 1990 could be written 04.VII.1990 or IV/VII/MCMXC, depending on whether the month is written as a number or spelled out in Roman numerals too, and whether the year is written in full or abbreviated.

Because a date needs three separate conversions plus consistent formatting, rather than one plain number, the Roman Numeral Date Converter is the better tool for birthdays, anniversaries, and tattoo designs: it takes a full date and outputs it in the formats people actually use for engravings and ink, plus the year on its own.

Common Uses for Roman Numerals Today

• Clock and watch faces
• Names of monarchs and popes (e.g., Elizabeth II, Pope Francis I)
• Movie and game sequel numbering (e.g., Rocky IV)
• Outlines and lists in documents
• Copyright dates for movies and TV shows
• Numbering of sporting events (e.g., Super Bowl LVIII)
• Book chapters and appendices
• Birthdays, anniversaries, and tattoos

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