How to use the Roman numeral converter
- 1 Type a number from 1 to 3,999 to get the Roman numeral.
- 2 Or type a Roman numeral such as MCMXC to get the number.
- 3 Read the working, which splits the value into thousands, hundreds, tens and ones.
- 4 Use the tables of symbols and common years for quick reference.
Writing Roman numerals correctly
Work from the largest place value down: thousands, hundreds, tens, then ones, writing each with its own letters. 1994 is M + CM + XC + IV = MCMXCIV. For numbers written out in words, use the Number to Words Converter.
- Never repeat V, L or D.
- Use subtraction only for 4, 9, 40, 90, 400 and 900.
- Double-check engraving text letter by letter before ordering.
Features
Both directions
Numbers to Roman numerals and back.
Working shown
See how each part of the number becomes letters.
Validation
Flags numerals that are not written in standard form.
When to use it
Tattoos and engravings
Dates such as wedding days are often written in Roman numerals; check them before engraving. For dates themselves, the Age Calculator and Date Difference Calculator can help.
Clocks and watches
Clock faces use I to XII, often with IIII instead of IV for balance.
Books and films
Chapter numbers, volume numbers and film copyright years use Roman numerals; MMXXVI is 2026.
Homework
Practise converting and check answers with the working shown.
Related Unit tasks
Frequently asked questions
How do Roman numerals work?
Seven letters stand for values: I 1, V 5, X 10, L 50, C 100, D 500 and M 1,000. Letters are added from largest to smallest, and a smaller letter before a larger one is subtracted, as in IV for 4.
What is 2026 in Roman numerals?
MMXXVI: MM for 2000, XX for 20 and VI for 6.
What is the largest Roman numeral?
In standard form, 3,999, written MMMCMXCIX. Larger numbers used a bar over a letter to multiply it by 1,000.
Is there a Roman numeral for zero?
No. The Romans had no symbol for zero; later writers sometimes used the word nulla.
Why is 4 written IV and not IIII?
Standard form uses subtraction to avoid four of the same letter. IIII appears on many clock faces by tradition.
Which subtractions are allowed?
Only I before V or X, X before L or C, and C before D or M. So 99 is XCIX, not IC.
How do I write 1990?
MCMXC: M for 1000, CM for 900 and XC for 90.
What is 50 in Roman numerals?
L.
Can lower-case letters be used?
Yes; the converter accepts both and shows the result in capitals, as is usual.
Why does the converter reject VV or IL?
They are not valid in standard form. V, L and D are never repeated, and only certain subtractions are allowed.
Are Roman numerals still used officially?
They are used for monarchs and popes, such as Charles III, for some book chapters and appendices, on clock faces, and for events such as the Olympic Games and the Super Bowl.
How do I read a Roman numeral quickly?
Split it into groups from left to right: thousands, hundreds, tens and ones. Read each group separately and add them, so MDCCLXXVI is one thousand, seven hundred, seventy and six.
Why are Roman numerals used on clocks?
They give a classic look and were traditional on public clocks long before Arabic numerals became common in Europe. Many watchmakers still use them for style.
How do I write 100 in Roman numerals?
One hundred is written as the single letter C, from the Latin word centum.
Built and reviewed by Hamza Farooq, founder and lead developer
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