Roman Numeral Converter
Convert any number to Roman numerals or read a numeral back as a number — and turn a full date into Roman numerals for a tattoo, wedding invitation or engraving. Every result comes with the breakdown showing exactly which symbols were used and why.
- Converts both ways
- Date to numerals mode
- Checks standard form
- Up to 3,999,999
Roman numeral converter
In Roman numerals
MMXXVI
Enter a number, a numeral or a date on the left and the conversion appears here instantly.
How it breaks down
Each block is one place value. Read them left to right and add them together.
Details
- Value—
- Roman numeral—
- Number of symbols—
- Standard form—
- Uses subtraction—
- Spoken as—
Quick reference chart
1 to 10
Tens
Hundreds and thousands
Tap any tile to load that value into the converter.
Why this Roman numeral converter is better
Converting is trivial. Getting a date right for something permanent, or checking whether a numeral you found is even valid, is where the useful work is.
A proper date mode
Pick a date, choose the order and the separator, and get the finished line. No converting three parts by hand and hoping you joined them correctly.
Validity checking
Numerals are tested against the standard rules. Something like IIII or IC is still read for you, but it is clearly flagged as non-standard rather than silently accepted.
The breakdown, not just the answer
See 2026 as MM plus XX plus V plus I, each block labelled with its value, so the pattern becomes obvious after one or two goes.
Beyond 3,999
Most converters stop at MMMCMXCIX. This one continues to 3,999,999 using the overline convention, where a bar multiplies a symbol by a thousand.
A chart you can click
The reference table is not a static image. Tap any value to load it straight into the converter and see its breakdown.
Instant, free, private
Everything runs in your browser with no sign-up and no advert wall, which matters when the date you are converting is a personal one.
How Roman numerals work
Seven letters, two rules and one habit that trips everybody up.
Learn the seven symbols
I is one, V is five, X is ten, L is fifty, C is one hundred, D is five hundred and M is one thousand. Every numeral is built from these and nothing else.
Add when values descend
Read left to right and add: XVII is ten plus five plus one plus one, which is seventeen. Symbols never repeat more than three times in a row.
Subtract when a smaller symbol comes first
IV is four, not six, and IX is nine. Only I, X and C may be used this way, and only before the next two larger symbols — so IV and IX are valid but IL and IC are not.
Build from the largest place value down
For 2026, take the thousands first (MM), then the tens (XX), then the units (VI). That order is exactly what the breakdown panel shows you.
Where you will need this
Roman numerals never went away — they just moved to the places where something needs to look permanent.
- Tattoos. Birth dates and anniversaries are the most common Roman numeral tattoo. Check the numeral twice here before anyone picks up a needle.
- Weddings and invitations. Dates on stationery, signage and engraved gifts are traditionally set in numerals.
- Homework and exams. Convert both directions and use the breakdown to understand where you went wrong rather than just copying an answer.
- Film and book credits. Copyright years in end credits are usually in numerals, which is why MMXVIII style strings turn up in searches.
- Clock faces and buildings. Decoding a cornerstone or a sundial is a one-tap job in Roman-to-number mode.
- Sport and events. Super Bowls, Olympiads and monarchs all carry numerals, and the numbers are now large enough to be worth checking.
Roman numeral FAQs
The rules, the edge cases and the ones people get wrong on permanent objects.
Why is four written IV and not IIII?
Standard form never repeats a symbol more than three times, so four is written as one before five. IIII does appear historically and is still used on many clock faces for visual balance, but it is not the standard form and would be marked wrong in an exam. This converter reads IIII correctly and tells you it is non-standard.
Is there a Roman numeral for zero?
No. The system has no symbol for zero and no way to write negative numbers or fractions of the sort we use today. Medieval scribes occasionally wrote the word nulla when a zero was needed. This is why the converter starts at one.
Which symbols can be subtracted?
Only I, X and C, and each only before the next two larger symbols. That gives exactly six valid subtractive pairs: IV, IX, XL, XC, CD and CM. Anything else, such as IL for forty-nine or IC for ninety-nine, is invalid however logical it looks.
How do you write numbers above 3,999?
With a vinculum, an overline drawn above a symbol to multiply it by one thousand. A barred V is five thousand and a barred X is ten thousand, which extends the system to 3,999,999. It is a later convention rather than classical practice, and this converter applies it automatically once you pass 3,999.
How should a date be written in Roman numerals?
Convert each part separately and join them with a dot, a dash or a slash. There is no single official standard, so day-month-year and month-day-year are both common; pick whichever matches how you would normally write the date. Zeros are dropped, so the fifth of a month is V, never OV.
What is the largest number you can write?
Without an overline the maximum is 3,999, written MMMCMXCIX, because there is no symbol above M and no more than three may be repeated. With the overline convention the practical limit is 3,999,999.
Are Roman numerals case sensitive?
No. Capitals are conventional and are what you should use for anything formal or permanent, but lower case carries the same values and is common in book prefaces and outline numbering. Type either here and the converter handles it.
Is anything I convert stored?
No. The conversion runs entirely in your browser. Nothing is sent to a server or saved, which matters given how often the number being converted is a personal date.
Convert it, then check it
Numbers, numerals and full dates in both directions, with the breakdown and a validity check on every result. Free, instant and with nothing to install — worth a second look before anything goes on skin, stone or paper.