Roman numerals converter

A Roman numerals converter that works both ways

This Roman numerals converter has a single box. Type a number and it writes the Roman numeral: 2026 gives MMXXVI. Type a Roman numeral, in capitals or lower case, and it shows the number: “mcmxciv” gives 1994. Use it to read a copyright year, check a date before a tattoo or help with homework. Everything is worked out in your browser and nothing is sent anywhere.

How to use it

1. In “Number or Roman numeral”, enter a number from 1 to 3,999,999 or Roman letters. The result appears in large type as you type.
2. “Step-by-step breakdown” shows the working: 1994 = 1000 + 900 + 90 + 4 = M + CM + XC + IV.
3. “Copy” puts the result on your clipboard. “Swap” moves the result into the box so you can convert it back.
4. Under “Date in Roman numerals”, pick a date, then choose the “Order” and the “Separator” (dot, hyphen, slash or space). The page starts with month, day, year: July 4, 2026 becomes VII.IV.MMXXVI.
5. Open “Roman numerals chart from 1 to 100” for a quick reference, with 500, 1000 and recent years listed below it.

The seven symbols and the rules

• Add. Symbols run from largest to smallest and are added up: VII = 5 + 2 = 7, CLX = 160.
• Subtract. A smaller symbol in front of a larger one is taken away. Only six pairs are allowed: IV (4), IX (9), XL (40), XC (90), CD (400) and CM (900).
• Three in a row at most. I, X, C and M are never repeated more than three times: 30 is XXX, but 40 is XL.
• V, L and D are never repeated and never subtracted: 100 is C, not LL, and 95 is XCV, not VC.

The converter enforces these rules. Type “IC” for 99 and it refuses, then gives the correct form, XCIX. The same goes for “IL” (49 is XLIX) and “XM” (990 is CMXC).

How to read a Roman numeral, step by step

Take MDCCLXXVI. Work from left to right and look for subtractive pairs; here there are none. Split it into M, DCC, LXX and VI: 1000 + 700 + 70 + 6 = 1776.

Large numbers and the bar above

With seven letters and no more than three repeats, the classic system ends at MMMCMXCIX, or 3,999. To go further, a bar drawn above a letter (a vinculum) multiplies it by 1,000. So 4,000 is I̅V̅, that is IV with a bar on top, and 50,000 is L̅. The converter uses this notation from 4,000 to 3,999,999 and shows a reminder under the result. Depending on the font on your device, the bar may sit slightly off-centre.

Where Roman numerals still appear

In English they are most familiar from the names of monarchs and popes (Henry VIII, Elizabeth I), from clock and watch faces, and from the copyright year in film and television credits. They number chapters, volumes, the acts of a play and the points of an outline. Sport uses them too: the Super Bowl played in February 2026 was Super Bowl LX. One difference from French, Spanish or Italian: centuries are normally written with ordinary figures or words, “the 21st century”, and a form like “XXI century” is rare in English.

Before a tattoo or an engraving

• Check the order. In the United States the month comes first; in the United Kingdom, Ireland and Australia the day does. July 4, 2026 is VII.IV.MMXXVI one way and IV.VII.MMXXVI the other. Use “Order” to switch.
• Write the year in full: MMXXVI, not XXVI, which reads as 26.
• There is no zero, as the Romans had no symbol for it, so March 5 is III.V with no leading zero.
• Ask someone else to read the result back before the appointment, and compare the stencil letter by letter.

Frequently asked questions

How do you write 2026 in Roman numerals?

MMXXVI: MM for 2000, XX for 20, VI for 6. The year 2024 was MMXXIV.

Why do some clocks show IIII instead of IV?

It is a clockmakers' tradition. The form IIII was already used in ancient Rome, and on a dial it balances the VIII on the opposite side. Several explanations are given and none is certain. In normal writing 4 is IV, and the converter says so if you type IIII.

How do you write 4,000?

With a bar above: I̅V̅. Without the bar, standard notation stops at 3,999.

What is the largest number?

Here it is 3,999,999: M̅M̅M̅C̅M̅X̅C̅I̅X̅CMXCIX. Without the bar, the limit is 3,999, written MMMCMXCIX.