Roman numeral converter. Both directions, instantly.
Enter a whole number from 1 to 3,999,999.
Letters I V X L C D M. For overline (thousands) values, wrap the group in parentheses, e.g. (V) for 5,000.
The seven symbols
Subtractive pairs (IV = 4, IX = 9, XL = 40, XC = 90, CD = 400, CM = 900) keep numerals short. Standard numerals only reach 3,999 (MMMCMXCIX). For larger values, Roman scribes drew an overline (vinculum) over a numeral to multiply it by 1,000: an overlined V is 5,000 and an overlined X is 10,000. This tool draws the overline above the result, and accepts (V) parenthesis notation when you type, since overlines are hard to enter on a keyboard.
How to use the Roman Numeral Converter
This converter turns whole numbers into Roman numerals and Roman numerals back into numbers, from 1 to 3,999,999. Standard numerals cover 1 to 3,999; above that the thousands are drawn with an overline, which multiplies them by 1,000. It is for students, designers and anyone dating a document, a tattoo or a building plaque.
Step by step
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Convert a number
Type a whole number in the top box, the one marked e.g. 2026. The numeral appears below as you type. The page opens with 2026, which reads MMXXVI. Commas and spaces are ignored, so 12,500 works.
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Convert a numeral
Type or paste a Roman numeral in the second box, marked e.g. MMXXVI. Capital or small letters both work, and spaces are ignored. The number appears below with thousands separators.
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Enter values above 3,999
Overlines are hard to type, so wrap the thousands group in parentheses. (V) is 5,000 and (V)CMXCIX is 5,999. Only the leading group may be in parentheses.
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Copy the result
Press Copy beside either result. A Roman result is copied in the parentheses form, because plain text cannot hold an overline. A number is copied as digits without commas.
Reading the result
- Up to 3,999 the result uses the seven standard symbols, ending at MMMCMXCIX. From 4,000 the thousands part is shown with a line over it and the rest follows plainly, so 5,999 shows an overlined V followed by CMXCIX.
- The decoder only accepts standard spellings. IV and IX are fine, but IIII, VX and IL are rejected with a message instead of being guessed at.
- Messages in place of a result tell you what to fix: digits only, no zero, a maximum of 3,999,999, or a numeral that is not valid.
Tips and common mistakes
- There is no Roman numeral for zero or for negative numbers. Fractions and decimals are not accepted either.
- When you paste a converted numeral into a design, replace the parentheses with a real overline in your design app, or keep the parentheses and explain them.
- Check the year carefully on anything permanent. Years in the 1990s are a common slip: 1999 is MCMXCIX, not MIM.
- The seven symbols card under the converter lists every letter's value for quick reference.
Privacy and limits
The conversion runs in your browser. Nothing you type is sent anywhere or saved, and the top box returns to 2026 when you reload the page. The largest value it handles is 3,999,999.
Everything the converter handles.
- Convert any number to Roman numerals, type a whole number and the numeral appears live as you type.
- Decode Roman numerals back to a number, paste any numeral and get the integer value, formatted with thousands separators.
- Work up to 3,999,999 using overline (vinculum) notation, drawn visually above the thousands group.
- Type overline values with parentheses, enter (V) for 5,000 or (X)CMXCIX for 10,999, no special characters needed.
- Get strict validation, malformed numerals like IIII, VX or IL are rejected with a clear message, not silently misread.
- Copy either result to your clipboard with one click.
Frequently asked questions.
Is the Roman Numeral Converter free?
Is it private? Is my data uploaded anywhere?
What is the largest number it supports?
How do I type an overline on a keyboard?
Is there a Roman numeral for zero?
Why does IIII or VX get rejected?
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