Roman Numeral Converter
Convert numbers to Roman numerals and back, up to 3,999,999 using bars over the letters. Choose standard or additive style, upper or lower case, and turn any date into Roman numerals.
Written by Suhaib Hassan. Figures are estimates you can edit. Our methodology.
It builds numerals by taking the largest value that fits at each step, and reads them by adding values and subtracting smaller letters that come before larger ones.
People need Roman numerals for dates, film credits, outlines and tattoos. This checks them and shows the working.
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| Part | Value | Numeral |
|---|
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Roman numeral reference
Seven letters give every number: I 1, V 5, X 10, L 50, C 100, D 500, M 1,000. A smaller letter before a larger one is subtracted. A bar over a numeral multiplies it by 1,000.
| Number | Standard | Additive | Note |
|---|---|---|---|
| 1 | I | I | Single strokes, the oldest form |
| 4 | IV | IIII | IIII is common on clock faces and older inscriptions |
| 5 | V | V | Five, the shape of an open hand |
| 9 | IX | VIIII | One less than ten |
| 10 | X | X | Ten, two crossed fives |
| 40 | XL | XXXX | Ten less than fifty |
| 50 | L | L | Fifty |
| 90 | XC | LXXXX | Ten less than one hundred |
| 100 | C | C | From centum, one hundred |
| 400 | CD | CCCC | One hundred less than five hundred |
| 500 | D | D | Five hundred |
| 900 | CM | DCCCC | One hundred less than one thousand |
| 1,000 | M | M | From mille, one thousand |
| 4,000 | I̅V̅ | MMMM | A bar over a numeral multiplies it by 1,000 |
| 5,000 | V̅ | V̅ | V with a bar |
| 10,000 | X̅ | X̅ | X with a bar |
| 1,000,000 | M̅ | M̅ | M with a bar, one million |
Formulas
How the numbers are worked out.
Number to Roman
Take the largest numeral value that fits, write it down, subtract, and repeat.
2026 = 1000 + 1000 + 10 + 10 + 5 + 1 = MMXXVIRoman to number
Add each value, but subtract a letter that stands before a bigger one.
MCMXCIV = 1000 + (1000 − 100) + (100 − 10) + (5 − 1) = 1994Large numbers
A bar (vinculum) over letters multiplies them by 1,000. In brackets, (V) also means 5,000.
(V)DC = 5,000 + 600 = 5,600Worked examples
Illustrative figures, each checked by hand. The first is the default setup.
Year 2026
Default.
Year 1994
Roman to number.
A big number
5,600.
How to convert Roman numerals
- Choose number to Roman, Roman to number, or date to Roman.
- Enter the number, numeral or date.
- Pick standard (IV) or additive (IIII) style.
- Read the result and the breakdown.
Roman numerals have no zero, no negative numbers and no fractions here. Numbers of 4,000 and above use the overline, and not all fonts draw the bar clearly.
By Suhaib Hassan · Reviewed 29 September 2026 · How CalculatePilot verifies formulas →
Sources
- Gordon, A.E., Illustrated Introduction to Latin Epigraphy, University of California Press, 1983.
- Unicode Consortium, The Unicode Standard, Number Forms and combining overline (U+0305).
- Ifrah, G., The Universal History of Numbers, Wiley, 2000.
Frequently asked questions
How do you write 4 in Roman numerals?
IV in standard notation. IIII (additive) is also seen, especially on clock faces.
What is the largest Roman numeral?
Classical numerals stop at 3,999 (MMMCMXCIX). A bar over a numeral multiplies it by 1,000, which here extends the range to 3,999,999.
Is there a zero in Roman numerals?
No. The Romans had no symbol for zero, though they had the word nulla.
Why is IIII on clocks?
It balances the face visually against VIII, and it has a long tradition. Both IV and IIII are historically valid.
How do I write a date in Roman numerals?
Convert the day, month and year each to numerals. 24 October 2026 becomes XXIV.X.MMXXVI.
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