Convert numbers, Roman numerals, and dates
Use the tool above to convert numbers, decode Roman numerals, or format a date. Choose a mode first, then enter the value in the fields it displays.
Choose a conversion mode
- Number → Roman converts numeric input.
- Roman → Number decodes Roman-numeral input.
- Date → Roman formats the values in the date fields.
Convert numbers to Roman numerals
- Select Number → Roman.
- Enter one value per line in the standard input, following its placeholder.
- Read the result in the read-only output field.
- Select Copy or Download to retrieve the result.
The visible numeric range is 1–3,999. The page does not document how blank lines, whitespace, mixed valid and invalid lines, or other edge cases are handled.
Decode Roman numerals
- Select Roman → Number.
- Enter or paste the Roman numeral in the standard input.
- Read the number in the read-only output field.
- Select Copy or Download to retrieve it.
The local page does not document how invalid sequences, unusual forms, whitespace, or letter case are handled.
Format a date as Roman numerals
- Select Date → Roman.
- Enter numeric values in Day, Month, and Year.
- Use the exposed ranges: Day
1–31, Month1–12, and Year1–3999. - Read the formatted result and select its Copy control.
The result uses Roman numerals separated by centered dots, such as XIV · III · MMXXVI. Tattoo Font Preview shows the result in the decorative font loaded by the page.
Load and retrieve text results
In a standard conversion mode, select Upload or drag a file anywhere on this page. The selected file is read as text and placed in the standard input. Standard output has Copy and Download; date output has Copy.
Accepted upload types, file-size limits, and generated download filenames are not documented.
Limits and privacy considerations
- Standard conversion shows a range of 1–3,999.
- Date fields show Day 1–31, Month 1–12, and Year 1–3999.
- Calendar validation beyond those exposed field ranges is not documented.
- Blank-line, whitespace, batch-error, and invalid-sequence handling is not documented.
Conversion and selected-file text reading occur in the browser. The page also loads Ahrefs Analytics, conditionally Google Analytics, and a local serif fallback for the decorative preview, so the implementation does not make an absolute claim about external font requests.
Frequently Asked Questions (FAQs)
What is the highest number I can convert to Roman numerals?
The standard conversion range on this page is 1 to 3,999. The highest supported value is MMMCMXCIX.
How do I convert a date to Roman numerals for a tattoo?
Select Date → Roman, enter the numeric Day, Month, and Year, then read the date output. Tattoo Font Preview displays the date in the available decorative font preview.
How do I decode a Roman numeral back to a number?
Select Roman → Number, enter the Roman numeral in the standard input, and read the converted value in the output field.
Is my data safe when I use this tool?
Conversion and selected-file text reading occur in the browser. The page loads shared Ahrefs Analytics and conditionally Google Analytics, and uses a local serif fallback for the decorative preview, so the implementation does not make an absolute claim about external font requests.