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Convert numbers to Roman numerals or Roman numerals to numbers using this calculator tool.

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Contents:

What are Roman numerals?

Roman numerals are a numeral system that originated in ancient Rome. They use combinations of letters from the Latin alphabet to represent values. Unlike our modern decimal system which uses 10 digits (0-9), Roman numerals use 7 basic symbols:

Roman numeralArabic
I1
V5
X10
L50
C100
D500
M1000

All other numbers are formed by combining these 7 basic symbols.

Roman numerals chart (1-100)

The chart below shows Roman numeral equivalents for numbers 1 through 100:

NumberRomanNumberRomanNumberRomanNumberRoman

How to convert Roman numerals to numbers

To convert Roman numerals into their decimal equivalent, follow these steps:

1
Identify each symbol and write down its corresponding value using the basic symbols chart above.
2
Compare adjacent symbols. If a smaller value appears before a larger value, subtract the smaller from the larger (e.g. IV = 5 − 1 = 4). If the smaller value appears after or is equal, add it.
3
Add up all the values to get the final number.

Example: MCMLXXXIV → M(1000) + CM(900) + L(50) + XXX(30) + IV(4) = 1984

How to read Roman numerals

Reading Roman numerals is a matter of understanding the additive and subtractive principles:

  • Additive: When a symbol of equal or greater value follows another, you add them together. Example: VII = 5 + 1 + 1 = 7
  • Subtractive: When a symbol of lesser value precedes one of greater value, you subtract the smaller. Example: IX = 10 − 1 = 9

The subtractive principle only applies in specific cases: I before V (4) or X (9); X before L (40) or C (90); C before D (400) or M (900).

Rules for Roman numerals

1
A symbol can be repeated up to 3 times consecutively (e.g. III = 3, XXX = 30), but never 4 times. Instead, the subtractive form is used (IV instead of IIII).
2
Symbols V, L, and D are never repeated. They represent 5, 50, and 500 respectively, and doubling them would equal the next symbol up (VV=X, LL=C, DD=M).
3
Only I, X, and C can be used as subtractive numerals, and only before the two symbols of next-higher value. I before V and X; X before L and C; C before D and M.

These rules keep Roman numeral representations standardized and unambiguous.

Roman numerals for larger numbers

The standard Roman numeral system only accommodates numbers up to 3,999 (MMMCMXCIX). For larger numbers, the Romans used a system where a bar (vinculum) placed over a numeral multiplies its value by 1,000:

Symbol with barValue
V̅5,000
X̅10,000
L̅50,000
C̅100,000
D̅500,000
M̅1,000,000

For example, the number 4,000 would be written as MV̅ (1000 + bar-V for remaining), though in practice large Roman numerals were rarely used with precision.

Common years in Roman numerals

YearRoman Numerals
1990MCMXC
2000MM
2010MMX
2020MMXX
2024MMXXIV
2025MMXXV
2026MMXXVI

History of Roman numerals

Roman numerals originated in ancient Rome, likely evolving from tally marks used by shepherds and traders. The system was the standard for writing numbers throughout Europe for nearly 2,000 years, from the founding of Rome (~753 BC) until the widespread adoption of Hindu-Arabic numerals in the late Middle Ages (around the 14th century).

The earliest forms of Roman numerals were simpler: I for 1, II for 2, and so on. The subtractive notation (IV instead of IIII) was a later refinement that made numbers more compact. Interestingly, some clock faces still use IIII instead of IV, a tradition thought to maintain visual symmetry with VIII on the opposite side.

Where are Roman numerals used today?

Despite being thousands of years old, Roman numerals remain widely used in modern times:

  • Clock and watch faces — many traditional timepieces use Roman numerals for the hours.
  • Movie and TV production dates — copyright dates in film credits (e.g. MMXXIV).
  • Super Bowl numbering — the NFL uses Roman numerals for each Super Bowl (e.g. Super Bowl LVIII).
  • Monarchs and popes — numbering of kings, queens, and popes (e.g. King Charles III, Pope Francis I).
  • Book chapters and outlines — for organizing content hierarchically.
  • Building cornerstones — to mark the year of construction.
  • Numbering of sequels — movies, games, and other media (e.g. Rocky IV, Final Fantasy XV).