Roman Numeral Converter

• Roman numeral converter that converts both ways between Arabic numbers (1–3999) and Roman numerals, with one-click copy of the result
• When converting Arabic → Roman it shows a symbol breakdown (e.g. M = 1000); when converting Roman → Arabic it shows step-by-step calculation
• Includes a Roman numeral reference (basic symbols, writing rules) and a quick-pick common numbers table you can click to fill in and convert

1. Open the tool page — no download or installation needed
2. Pick a direction at the top (Arabic → Roman / Roman → Arabic) and type a number or Roman numeral into the input box
3. Conversion runs automatically as you type (or click "Convert"); click "Copy" to grab the result

• Arabic input must be an integer from 1 to 3999; Roman input must follow the writing rules, otherwise an error is shown
• This tool is completely free and needs no sign-up. All calculation runs locally in your browser — your data never leaves your device

Free online Roman numeral conversion tool, supports mutual conversion between Arabic numbers and Roman numerals, provides step-by-step conversion breakdown and common number reference. Suitable for learning Roman numerals, historical research, programming development and other scenarios.

Open the tool page — no download or installation needed Pick a direction at the top (Arabic → Roman / Roman → Arabic) and type a number or Roman numeral into the input box Conversion runs automatically as you type (or click "Convert"); click "Copy" to grab the result

Arabic input must be an integer from 1 to 3999; Roman input must follow the writing rules, otherwise an error is shown This tool is completely free and needs no sign-up. All calculation runs locally in your browser — your data never leaves your device

Yes, Roman Numeral Converter is completely free. No download or installation required — it runs right in your browser.