Roman Numeral Converter

Say Hello to Simplicity

Use this roman numeral converter to change numbers and Roman numerals both ways.

Enter a whole number from 1 to 3999 or a valid Roman numeral.

Click Convert or press Enter to see the answer.

The tool shows the result and a short explanation.

It follows standard Roman numeral rules for clear output.

How It Works

The single input box accepts one value.

For numbers, use digits only.

Range is 1 to 3999.

For Roman numerals, use I V X L C D M.

Uppercase and lowercase both work.

Use standard forms such as IV for 4.

Also use IX for 9 and XL for 40.

You can also use XC for 90.

Use CD for 400.

Use CM for 900.

After conversion you see a line like 42 = XLII.

The second line explains the result in words.

Both lines appear below the button.

Here are the messages you may see.

• “Please enter a value to convert”
• “Invalid Roman numeral”
• “Please enter a valid integer between 1 and 3999”

Keep these notes in mind.

• The tool supports values from 1 to 3999.
• Use whole numbers only.
• Roman numerals follow standard rules.
• The tool trims spaces at the start or end.
• Lowercase letters convert to uppercase automatically.
• Overlines and other extended forms stay outside the supported set.
• The converter returns the standard form for each value.

Step-by-Step Instructions

1. Click the input box.
2. Type a whole number from 1 to 3999, or a Roman numeral.
3. Click Convert or press Enter.
4. Read the bold result line.
5. Read the explanation line just below.
6. Change the input and convert again.

Why You’ll Dig This Tool

This roman numeral converter handles both directions with speed and clarity.

Here are common use cases.

• Students check homework and study notes.
• Teachers prepare quizzes and answer keys.
• Editors format prefaces and appendices with Roman page numbers.
• Designers set years on logos or plaques.
• Watch fans plan clock faces and dials.
• Developers and analysts check values in code or sheets.

Try these sample conversions.

• 2024 becomes MMXXIV.
• XLII becomes 42.
• MCMXC becomes 1990.

A Little Fun History

Roman numerals use seven letters with set values.

• I means 1
• V means 5
• X means 10
• L means 50
• C means 100
• D means 500
• M means 1000

Place a smaller value before a larger one to subtract in set cases.

IV means 4 and IX means 9.

XL means 40 and XC means 90.

CD means 400 and CM means 900.

The converter applies these rules for every result.

It gives the standard form for each number.

Get Started Now

Enter a value and click Convert to begin.

Press Enter if you like keyboard speed.

Keep numbers within 1 to 3999 for the best experience.

Use standard Roman forms for letter input.

That is it.

You are ready to convert.