Roman Numeral Converter

A Roman numeral converter translates ordinary numbers into Roman numerals and back. Enter 2026 and it returns MMXXVI (2000 + 20 + 6); paste MCMLXXXIV and it returns 1984. This free tool handles every whole number from 1 to 3999 in both directions, with a symbol-by-symbol breakdown so you can check the math yourself.

Roman numerals are everywhere once you start looking: the copyright year at the end of a film (MMXXVI for 2026), Super Bowl titles, the chapters of a book, monument inscriptions, clock faces, and the suffixes after a name like Henry VIII. The converter builds MMXXVI by taking the largest pieces it can: 1000 + 1000 (MM) for 2000, 10 + 10 (XX) for 20, and 5 + 1 (VI) for 6. Read the result left to right, largest values first, and you get the year exactly as you would see it on a film's end credits.

This converter is one of our everyday time-and-number tools, each aimed at a different job. Reach for the Date Calculator to count the days between two dates before formatting one as a numeral, the Age Calculator to turn a birth year into an exact age, the Time Calculator to add or subtract hours and minutes, and the Tip Calculator to split a bill. This page is purely for translating numbers to and from Roman numerals.

The seven Roman numeral symbols

Every Roman numeral is built from just seven letters. Memorizing their values is the whole game:

A handy mnemonic for the order M, D, C, L, X, V, I is "My Dear Cat Loves Xtra Vitamins Intensely." Once you know the letters, the rest is just two rules: when to add and when to subtract.

The two rules: adding and subtracting

Rule 1: add when going down. When symbols are written in order from larger to smaller, you add them. So VIII is 5 + 1 + 1 + 1 = 8, and CLX is 100 + 50 + 10 = 160. This is the default behavior, and most of a numeral works this way.

Rule 2: subtract when a smaller symbol comes first. When exactly one smaller symbol sits immediately before a larger one, you subtract it. The GPO Style Manual puts both rules in one line: "a letter placed after one of greater value adds to it; a letter placed before one of greater value subtracts from it." The standard modern form allows only six subtractive pairs:

That is the entire system. Combine the additive default with these six subtractive shortcuts and you can write or read any number up to 3999.

Symbol reference table

This table shows every symbol and subtractive pair, with a small example of each in use:

Roman numeral place-value chart: build any number from 1 to 3999

The fastest way to write any number in Roman numerals is to convert each digit by its place (ones, tens, hundreds, thousands) and then string the pieces together largest-first. This chart gives the Roman form of every digit 1 to 9 in each place. Look up each digit of your number, read across, and join the results.

The thousands column stops at 3 (MMM = 3000) because M can repeat only three times in the standard modern form, which is exactly why the converter caps at 3999. From 4,000 up, the traditional notation puts a line over a letter to multiply it by 1,000 (the "overline" cells above). Note how each place mirrors the same shape: 4 is always "one before five" (IV, XL, CD) and 9 is always "one before ten" (IX, XC, CM).

How to use this converter

The tool has two tabs, so you can go in either direction:

1. Number → Roman: select the first tab and type a whole number from 1 to 3999. The Roman numeral appears instantly, along with a table showing which symbol value contributes what.
2. Roman → Number: select the second tab and type a Roman numeral (upper or lower case). The number appears, plus a line-by-line breakdown marking which letters were added and which were subtracted.
3. Use the quick examples: the chips under each input (like 4, 9, 40, or MMXXVI) fill the field for you, which is handy for spot-checking the tricky subtractive cases.
4. Watch for validation: if you enter something out of range or a malformed numeral, the tool explains why and, where it can, suggests the correct spelling instead of guessing silently.

Worked example 1: writing 49 (and why it isn't IL)

A classic trap. To write 49, you might be tempted by "IL", one before fifty. But in the standard form only I, X and C are ever subtracted, and only from the next two larger symbols: I from V and X, X from L and C, C from D and M. The correct path is 40 + 9 = XL + IX = XLIX. Break it down: XL is 50 minus 10 (40), and IX is 10 minus 1 (9). Together, XLIX = 49, the same value the GPO Style Manual table lists for 49. The converter flags IL and points you to XLIX.

Worked example 2: decoding MCMLXXXIV

Suppose you find MCMLXXXIV on a building. Read it in chunks, left to right: M = 1000, CM = 900, L = 50, XXX = 30, IV = 4. Add them up: 1000 + 900 + 50 + 30 + 4 = 1984. The two subtractive pairs (CM and IV) are the only places you subtract; everything else simply adds. Paste it into the "Roman → Number" tab and you will see exactly this sequence.

Worked example 3: the year 3999, the upper limit

The largest value this tool produces is 3999 = MMMCMXCIX. It splits as MMM (3000), CM (900), XC (90), and IX (9). You cannot go higher in the standard modern form because M can repeat only three times, capping the thousands at 3000. To represent 4,000 or more, a bar (vinculum) is drawn over a symbol to multiply it by 1,000: the GPO Style Manual lists V with a bar as 5,000 and M with a bar as 1,000,000, and gives 4,000 as MMMM or as M followed by a barred V. Those forms are rare today and hard to type, so the converter stops at 3999.

Step-by-step: write 1994 in Roman numerals

To see the place-value method in action, here is 1994 converted one place at a time. Split it into 1000 + 900 + 90 + 4, convert each part, then read the parts top to bottom (largest first) to get the final numeral.

1994 is a good stress test because three of its four places (900, 90, and 4) need a subtractive pair. That is why MCMXCIV looks busy, even though the method behind it is just four small lookups from the chart above.

Who this converter is for

• Students learning the system for a math or history class, who want to check homework and see the breakdown.
• Writers and editors formatting copyright dates, volume numbers, outline headings, or appendix labels.
• Designers and tattoo artists rendering a meaningful year or date and wanting to confirm the spelling before it is permanent.
• Genealogists and history buffs decoding dates on gravestones, cornerstones, and old documents.
• Trivia and puzzle fans who just need a fast, accurate translation in either direction.

Key terms explained

• Additive notation: writing symbols in descending order and summing them (LXVI = 50 + 10 + 5 + 1 = 66).
• Subtractive notation: placing one smaller symbol before a larger one to subtract it, using only IV, IX, XL, XC, CD and CM.
• Vinculum: an overline placed above a numeral to multiply its value by 1,000, used for numbers of 4,000 and up (V with a bar is 5,000). Not supported here.
• Place value: the idea that a digit's position changes its value (the "2" in 20 vs 200). Roman numerals have no place value, which is why they are clumsy for arithmetic.
• Canonical form: the single standard spelling of a number under the modern rules. Each value from 1 to 3999 has exactly one, which is why the converter flags variants such as IIII, IC and IL and shows the standard form instead.

A short history

Roman numerals grew out of marks used by the ancient Romans and dominated European counting for well over a thousand years. They were gradually displaced for calculation by the Hindu-Arabic system (the 0 to 9 digits we use today), which has both a zero and place value, making addition, multiplication, and long division far easier. Roman numerals never disappeared, though. They survive wherever a number is meant to feel formal, traditional, or decorative: on clock faces, in book front matter, in the names of monarchs and popes, and in the year stamped on films and buildings.

Popular Roman numeral conversions

Some numbers come up far more often than others: usually recent years, round milestones, and the values stamped on movies, copyrights, and anniversaries. Here are common conversions you can verify in the tool above:

Notice the pattern in the years: every "9" decade or century forces a subtractive pair. 1990 needs CM (900) and XC (90); 2024 needs the IV at the end. Those subtractive spots are where most handwritten Roman numerals go wrong, so they are worth double-checking.

Every year from 2000 to 2030 in Roman numerals

Years are among the most common things people convert, for tattoos, wedding dates, copyright lines, and anniversaries. Because 2000 = MM, every year this century simply reads MM followed by the tens and ones. Here is the full run from 2000 to 2030 with each breakdown; type any of them into the tool above to confirm.

Two years in this range trip people up: 2004 (MMIV, not MMIIII) and 2009 (MMIX, not MMVIIII). Both end in a subtractive pair, so double-check them if you are writing the numeral by hand.

Encoding vs decoding: which direction do you need?

People reach for this tool for two opposite jobs, and the converter handles both with its two tabs.

Encoding (Number → Roman) is for when you know the value and want the letters, most often a year for a tattoo, a wedding date, a copyright line, or a chapter heading. You type 2026 and read back MMXXVI. The risk here is producing a non-standard form by hand (writing XXXX instead of XL), which the converter avoids by always returning the single canonical spelling.

Decoding (Roman → Number) is for when you found the letters and want the value: reading a cornerstone, a film's release year, a clock, or a monarch's title. You paste MCMLXXXIV and read back 1984. The risk here is misreading a subtractive pair as additive (treating CM as 1100 instead of 900), which the line-by-line breakdown prevents by labeling each step. When accuracy matters, do both: encode your number, then decode the result, and confirm you land back where you started.

Tips for reading and writing them

• Work by place: convert thousands, hundreds, tens, and ones separately, then join them (1984 = 1000 + 900 + 80 + 4 = M + CM + LXXX + IV).
• Only six subtractions are standard: if a pair is not IV, IX, XL, XC, CD or CM, it is not a standard subtraction.
• Never repeat more than three: III is fine, IIII is not; the fourth step is always a subtractive pair.
• V, L and D never repeat: you will never see VV, LL or DD, because the next larger symbol replaces them.
• When in doubt, verify both ways: convert your number to Roman, then convert that result back. If you land on the original number, the spelling is right.

Limitations and assumptions

This converter sticks to the common, modern standard taught in schools. Keep these boundaries in mind:

• It covers 1 to 3999 only. There is no symbol for zero or negative numbers, and 4,000 and above need the overline (vinculum), which is not supported.
• It uses strict canonical spelling. Forms that clock faces or older tables use, such as IIII for 4, IC for 99 (listed in the GPO Style Manual table) or MDCCCC for 1900, are flagged with the standard spelling rather than silently accepted.
• It handles whole numbers only. The ancient fractional symbols (such as S for one half) are not part of normal Roman numerals and are out of scope.
• It ignores ornamental and medieval variants such as the "apostrophus" forms or additive year styles; the goal is one unambiguous result per value.

Related concepts and tools

Roman numerals are a number system without place value or a zero, which makes them a useful contrast to the decimal system you use every day. The most common reason people reach for them is dates and years, where this tool handles the formatting and a sister calculator handles the arithmetic:

• To count the days, months, or years between two dates before formatting one as a numeral, use the Date Calculator.
• To work out an exact age or anniversary from a birth or event year, use the Age Calculator.
• To find which week of the year a Roman-dated event falls in, see the Week Number Calculator.
• To see how place-value systems write the same number, try the Binary Calculator (base 2) or the Hex Calculator (base 16); the Scientific Notation Calculator shows the powers-of-ten shorthand for very large and very small numbers.

For other quick everyday conversions, browse the Everyday & Time category.

Sources

• U.S. Government Publishing Office, GPO Style Manual (2016), Chapter 12 "Numerals": rule 12.3 (Arabic numerals are preferable to Roman numerals) and rule 12.29 with the table of Roman numerals and dates.