Roman Numeral Converter — Step-by-Step Solutions

The Roman Numeral Converter translates between Roman numerals (I, V, X, L, C, D, M) and standard Arabic numbers. It supports four modes: number to Roman numeral, Roman to number, a reference chart from 1 to 100, and date to Roman numeral conversion.

Enter any number from 1 to 3,999 or a valid Roman numeral string to get instant conversion. The chart mode provides a handy reference for common values.

Number (1-3999)

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How to Use the Roman Numeral Converter

Number to Roman: enter a whole number from 1 to 3999 and get its Roman numeral with the symbol-by-symbol breakdown.
Roman to Number: type a Roman numeral using the letters I, V, X, L, C, D and M (upper or lower case). The value is shown with the way each symbol was added or subtracted.
Chart (1-100) lists every Roman numeral from 1 to 100 so you can look them up. Date to Roman converts a calendar date to day.month.year in Roman numerals, such as XXV.XII.MMXXV.
The standard system has no zero and no fraction. Numbers above 3999 would need a bar over the letters, which this tool does not use.

Formula and Theory

Roman numerals write numbers with seven letters: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500 and M = 1000. Values are built by adding the symbols from largest to smallest, so XVI is 10 + 5 + 1 = 16.

When a smaller symbol comes before a larger one, it is subtracted. IV is 5 - 1 = 4, IX is 9, XL is 40, XC is 90, CD is 400 and CM is 900. Only I, X and C can be used this way, and only before the next two higher symbols (I before V or X, X before L or C, C before D or M).

The same symbol is not repeated more than three times in a row, so 4 is IV rather than IIII, and 40 is XL. Because the largest symbol is M, the standard system stops at 3999 (MMMCMXCIX).

To convert a number, split it by place value (thousands, hundreds, tens, ones) and write each part: 1994 is 1000 + 900 + 90 + 4 = M + CM + XC + IV = MCMXCIV. To convert back, add each symbol, subtracting it when the symbol after it is larger.

Worked Examples

Example 1: Number to Roman numeral

Problem: Write 2024 in Roman numerals.

Solution: Split by place value: 2000 + 20 + 4. 2000 = MM, 20 = XX, 4 = IV. Join them: MM + XX + IV = MMXXIV.

Answer: MMXXIV

Example 2: A number that needs subtraction

Problem: Write 1994 in Roman numerals.

Solution: 1994 = 1000 + 900 + 90 + 4. 1000 = M, 900 = CM, 90 = XC, 4 = IV. Join: M + CM + XC + IV = MCMXCIV.

Answer: MCMXCIV

Example 3: Roman numeral to number

Problem: Convert MCMLXXXIV to a number.

Solution: Read left to right: M = 1000. CM = 900 (C is before M, so subtract: 1000 - 100). L = 50, X = 10, X = 10, X = 10. IV = 4 (I before V). Add: 1000 + 900 + 50 + 30 + 4 = 1984.

Answer: 1984

Example 4: The largest standard numeral

Problem: Write 3999 in Roman numerals, and the longest numeral below 4000.

Solution: 3999 = 3000 + 900 + 90 + 9 = MMM + CM + XC + IX = MMMCMXCIX. The longest numeral in the standard range is 3888, which is MMMDCCCLXXXVIII (15 letters): 3000 = MMM, 800 = DCCC, 80 = LXXX, 8 = VIII.

Answer: 3999 = MMMCMXCIX; 3888 = MMMDCCCLXXXVIII

Example 5: A date in Roman numerals

Problem: Write 25 December 2025 as a Roman numeral date.

Solution: Convert each part: day 25 = XXV, month 12 = XII, year 2025 = MMXXV. The date is shown as day.month.year.

Answer: XXV.XII.MMXXV

Frequently Asked Questions

How do I convert a number to Roman numerals?

Break the number into thousands, hundreds, tens and ones, write each part with the symbols M, C, X, I (and the 5-symbols D, L, V), then join them. For 49 that is 40 + 9 = XL + IX = XLIX.

Why is 4 written IV and not IIII?

The standard rule uses subtraction to avoid four of the same symbol in a row. IIII does appear on some clock faces as a tradition, but the standard form is IV.

What is the largest Roman numeral?

In the standard system the largest is 3999, written MMMCMXCIX. Larger numbers traditionally used a bar over a numeral to multiply it by 1000.

Is there a Roman numeral for zero?

No. The Roman system had no zero. Medieval texts sometimes used the word nulla, but there is no numeral symbol for it.

Can I use lowercase letters?

Yes. The converter accepts lowercase and uppercase letters and shows the result in capitals.

Why are Roman numerals still used?

They appear in clock faces, book chapters and prefaces, outline lists, film and event series (such as numbered sequels), regnal names of monarchs and copyright dates on some buildings.