Roman Numeral Converter
Convert numbers to Roman numerals and back, with a symbol-by-symbol breakdown.
2026 in Roman numerals
MMXXVI
How it breaks down
M
1,000
M
1,000
X
10
X
10
V
5
I
1
Romans wrote numbers by adding symbols from largest to smallest, with a smaller symbol placed before a larger one meaning subtraction — IV is 4, not 6. There is no zero, and no standard way to write anything above 3,999 without an overline notation.
Convert Arabic numbers to Roman numerals and back, with a symbol-by-symbol breakdown showing exactly how the result was built — useful for checking dates on buildings, movie credits, or just brushing up on how the numeral system actually works.
Handles the subtractive notation rules (like IV for 4, not IIII) that trip people up when converting by hand.
The seven symbols
| Symbol | Value | Subtractive pair | Gives |
|---|---|---|---|
| I | 1 | IV, IX | 4, 9 |
| V | 5 | — | — |
| X | 10 | XL, XC | 40, 90 |
| L | 50 | — | — |
| C | 100 | CD, CM | 400, 900 |
| D | 500 | — | — |
| M | 1000 | — | — |
Only I, X and C are ever used subtractively, and only before the next two symbols up. VL, IC and IM are not valid notation.
Reading a numeral by hand
- Work left to right through the symbols.
- If a symbol is worth the same or less than the one before it, add its value.
- If it is worth more than the one before it, subtract the previous value instead of adding it, then add this one.
- Worked example — MCMXCIV: M is 1000. CM is 900 (C before M). XC is 90. IV is 4. Total 1994.
- Sanity check: no symbol should repeat more than three times in a row in standard notation.
Why clock faces often show IIII
Plenty of clocks use IIII rather than the 'correct' IV for four, and it isn't a mistake. Several explanations circulate — visual balance against the VIII opposite it, casting convenience when numerals were made in sets, and the fact that subtractive notation was never universal in Roman practice anyway.
Roman usage was less standardised than school teaching suggests: IIII, VIIII and other additive forms appear throughout genuine Roman inscriptions. The strict subtractive rules were formalised long afterwards. This converter follows the modern standard form.
Frequently asked questions
- What is the largest number Roman numerals can represent?
- Standard notation typically goes up to 3,999 (MMMCMXCIX) before repeated symbols become impractical; larger numbers use an overline notation for multiplication by 1,000.
- Why is 4 written as IV instead of IIII?
- Roman numerals use subtractive notation for four of the nine digits within each power of ten — IV (5−1) is standard, though IIII does appear historically, e.g. on some clock faces.
- Can this convert Roman numerals back to a regular number?
- Yes — paste in a Roman numeral and it converts it back to its Arabic numeral value, with validation for improperly formed numerals.
- Is there a Roman numeral for zero?
- No. The system has no symbol for zero and no concept of it as a number — one of the reasons it's so poor for arithmetic compared with positional notation.
- How do I read a date like MCMLXXXIV on a building?
- Break it into parts: M (1000) + CM (900) + LXXX (80) + IV (4) = 1984. Paste it above to see the same breakdown done for you.