Roman numerals converter
Type 2026 or MMXXVI, either way round works. Strict validation catches malformed numerals, and the chart is right below when memory wobbles.
Guide
How to use it
- Type a number (1 to 3,999,999) or a numeral (like MCMXCIV), the direction is detected.
- Numbers above 3,999 use the vinculum: an overline multiplying the letter by 1,000.
- Non-standard numerals (like IIII) are read loosely with a note showing the standard form.
- The reference below covers the seven symbols and 1 to 100.
Examples
Numerals people actually look up
The film-credits classic: M (1000) + CM (900) + XC (90) + IV (4). Three subtractive pairs in one number, which is why nobody reads it at speed.
This year, and mercifully simple: two Ms, two Xs, VI. The 2000s are a kind decade for numerals, 1988 (MCMLXXXVIII) was not.
The NFL skipped the numeral for Super Bowl 50, a lone L looked odd, resuming with LI. Even billion-dollar brands negotiate with this system.
Method
How it works
To numerals: greedy assembly from the largest values down, using the six subtractive pairs (IV, IX, XL, XC, CD, CM) where the notation demands them. From numerals: values sum left to right with a smaller-before-larger read as subtraction, then the result is re-encoded and compared, only round-trip matches count as standard.
The loose-reading fallback handles clock faces (IIII) and older inscriptions honestly: you get the value, plus the standard spelling for anything you are about to engrave.
FAQ
Frequently asked questions
Why is 4 written IV and not IIII?
Standard modern form is IV, but IIII survives on clock faces by centuries-old convention (visual balance with VIII is the usual story). Both are readable, one is standard.
Is there a zero?
No. Roman numerals count things, and the Romans had no numeral for none. Zero reached Europe with Hindu-Arabic numerals a millennium later.
How do numerals above 3,999 work?
The vinculum: an overline multiplies by 1,000, so V̅ is 5,000 and X̅ is 10,000. This tool writes them with Unicode combining overlines, which copy as text.
Can a numeral repeat a letter four times?
Not in standard form: three repeats maximum (XXX is 30, XXXX is not 40, XL is). V, L and D never repeat at all.
Why do tattoos and watches use numerals?
Dates as numerals carry formality without language, and they age well, the date page here formats birthdays and anniversaries exactly for that use.
Do Romans deserve credit for the system?
They inherited and adapted Etruscan tally marks. The subtractive shorthand came late and stayed inconsistent until well after Rome, standardisation is largely medieval and modern.
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