What's the valid number range?

Standard Roman numerals support whole numbers from 1 to 3999.

Does it validate malformed Roman numerals?

Yes, an invalid or non-canonical numeral (like IIII) shows a clear error.

Is lowercase input accepted?

Yes, Roman numeral input is automatically uppercased before conversion.

Is my data uploaded to a server?

No. This tool runs entirely in your browser using standard web APIs, so your input never leaves your device and nothing is logged or stored on our servers.

Does it work offline and on mobile?

Yes. Once the page has loaded it keeps working without a network connection, and the layout is responsive so it stays usable on phones and tablets.

Roman Numeral Converter

Convert between numbers and Roman numerals.

Support

Works Offline

Privacy First

No Login

No API

Number → Roman numeral

Number (1–3999)

MCMXCIV

Roman numeral → Number

Roman numeral

1994

About the Roman Numeral Converter

Convert whole numbers from 1 to 3999 into Roman numerals, or decode Roman numerals back into standard numbers, with validation for malformed input.

Examples

Year 1994

Output

MCMXCIV

Keyboard shortcuts

Copy the main outputCtrl / ⌘ + Shift + C
Download the resultCtrl / ⌘ + S
Share this toolCtrl / ⌘ + Shift + S
Reset the inputsAlt + R
Open the tool search paletteCtrl / ⌘ + K

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Frequently asked questions

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Version 1.0.0 · Updated 2026-08-06 · Runs entirely in your browser