Roman Numeral Converter
Type a number to see it in Roman numerals, or type a Roman numeral to read it. Every result shows how it is built.
- Both directions
- Up to 3,999,999
- Step-by-step
- Checks invalid numerals
What is a Roman numeral converter?
Roman numerals write numbers with seven letters: I (1), V (5), X (10), L (50), C (100), D (500) and M (1,000). Symbols are added from largest to smallest, except where a smaller symbol before a larger one means subtraction: IV is 4, IX is 9, XL is 40, XC is 90, CD is 400 and CM is 900. This converter works in both directions, explains each result as a sum of parts, and rejects non-standard forms such as IIII or VX, telling you the correct form instead. Numbers above 3,999 use an overline (vinculum), which multiplies a numeral by 1,000.
How to convert Roman numerals
- Type a number such as 2026 in the Number box. The Roman numeral appears instantly: MMXXVI.
- Or type a Roman numeral such as XLII in the Roman numeral box to see its value: 42.
- Read the breakdown to see how the numeral is built, for example MM + XX + VI.
- Copy the result. Tick Lowercase for outlines and page numbers such as iv or xii.
Roman numeral rules
- Add values from left to right when they decrease or stay the same: VI = 5 + 1 = 6, XXX = 30.
- Subtract when a smaller numeral comes before a larger one, but only I before V/X, X before L/C and C before D/M.
- Never repeat a symbol more than three times in a row: 4 is IV, not IIII (clock faces are a traditional exception).
- V, L and D are never repeated or subtracted. There is no Roman numeral for zero.
Why use this roman numeral converter
- Converts as you typeNo Convert button: edit either side and the other updates immediately.
- Explains every answerEach numeral is broken into parts so you can check homework or learn the rules.
- Catches mistakesNon-standard numerals such as IC or MDCCCCX are flagged with the correct form.
- Private by designEverything is calculated in your browser. Nothing you type is sent to a server or saved.
Common uses
- Years and dates. Copyright years, film credits, building cornerstones and the Super Bowl.
- Homework. Check conversions and see the working.
- Clock faces and design. Get the right numerals for watches, logos and invitations.
- Outlines and chapters. Lowercase numerals for prefaces, lists and legal documents.
Related converters: Roman numeral date converter, Morse code translator. Browse all encoding tools.
Example: 1994 in Roman numerals
1994 = 1000 + 900 + 90 + 4 = M + CM + XC + IV = MCMXCIV
What to expect from the result
Standard Roman numerals stop at 3,999 (MMMCMXCIX). Larger numbers use the vinculum convention, where a bar over a numeral multiplies it by 1,000; these display with combining overline characters, which some fonts render imperfectly. Zero, negatives and fractions have no standard Roman form.
Roman Numeral Converter questions
What is 2026 in Roman numerals?
2026 is MMXXVI: MM (2000) + XX (20) + VI (6). 2027 is MMXXVII.
How do you write 4 and 9 in Roman numerals?
4 is IV (5 − 1) and 9 is IX (10 − 1). Writing IIII for 4 appears on some clock faces but is not standard.
What is the largest Roman numeral?
With standard symbols, 3,999 (MMMCMXCIX). With an overline meaning ×1,000, this converter goes up to 3,999,999.
Is there a Roman numeral for zero?
No. Romans had no symbol for zero. Medieval texts sometimes used the word “nulla” or the letter N.
Why is my Roman numeral invalid?
It breaks a rule, such as repeating a symbol four times (IIII), subtracting the wrong symbol (IC for 99) or subtracting from too large a value (VX). The converter shows the standard form instead.