Roman Numeral Converter
CalculatorsEnter a number in either form — Arabic or Roman — to convert it to the other.
Roman Numeral Converter
Convert Roman numerals to Arabic numbers or Arabic numbers to Roman numerals.
Roman numerals appear in many historical records and objects. They are commonly found on gravestones and monuments, in church and civil registers, and in legal documents.
They may also be used for volume, book, folio, page, or clause numbers. English legal records can use Roman numerals for regnal years, such as the year of a monarch’s reign.
The calculator uses standard notation, so IIII should be entered as IV. A form in a record that differs from the calculator’s is more often a historical variant than a mistake.
Reading a numeral
How do I read a Roman numeral?
Each Roman numeral represents a value: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1,000.
When a smaller value follows a larger one, the values are added. When a smaller value comes before a larger one, it is subtracted.
For example, MDCCCLII is 1,852: M (1,000) + D (500) + CCC (300) + L (50) + II (2).
Can Roman numerals be used for dates?
Yes. Roman numerals were commonly used for years on gravestones, monuments, and other inscriptions. For example, MDCCLXXVI represents 1776.
When transcribing a historical date, it is useful to preserve the date as it appears in the source and record the Arabic equivalent separately if needed.
Historical forms
Why is 4 sometimes written IIII instead of IV?
Modern convention usually writes 4 as IV, but subtractive notation was not consistently standardized when many historical records were created. IIII is a normal historical form and can be found on clocks, monuments, gravestones, and manuscripts.
What about Roman numerals written in lowercase?
Historical records may use lowercase Roman numerals, particularly in manuscripts and early printed works. A clerk might write iij for 3 or xxiij for 23.
A final j was sometimes used instead of the last i so that additional strokes could not easily be added to the number. These are variant forms rather than different numerical values.
The calculator uses standard notation, so iij should be rewritten as III before entering it. Case does not matter when entering a standard Roman numeral.
The upper limit
What is the largest number that can be written in standard Roman numerals?
Standard Roman numeral notation runs from 1 through 3,999, with 3,999 written as MMMCMXCIX.
Larger numbers were sometimes represented by placing a bar over a numeral, multiplying its value by 1,000. That notation is outside the standard form used by this calculator and is uncommon in the kinds of historical records where genealogists typically encounter Roman numerals.