Roman Numeral Converter

Online Roman numeral and Arabic numeral converter, supporting single and batch conversion

Browser execution mode: Your data is processed in your browser and is not uploaded to the server.

Speed and Stability: Processing speed depends on your device and browser. For large batch work, the desktop version may be more stable.

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If the online tool fails to load or run, try the desktop tool.https://tools.yikeaigc.com/

Tool Usage

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Set the conversion direction and validation rules first, then enter a number or load sample data. Single conversions preview in real time; for batch conversion, paste text or select multiple TXT/CSV files.

1Set conversion rules

2Enter or select files

3View and download results

1Processing mode Light switch, no complex page needed

2Conversion direction Auto-detect, ideal for mixed batch data

Arabic numbers to Roman numeralsExample: 2026 to MMXXVI Roman numerals to Arabic numbersExample: MCMXCIV to 1994 Auto-detect and convertDetect each input type and output the other format

Strictly validate standard Roman numerals Normalize case and common Roman symbols Include error rows in export

3Batch and export settings Settings are saved on this device

Batch delimiter

Text result style

File export format

Preview rows

Ready with default rules. Enter content to start converting.

4Enter a single number Supports 1-3999 and I-MMMCMXCIX

Live Result

Waiting for input

Set the conversion direction, then enter content.

4Batch input or upload files For multiple files, only the first 20 names are shown; all files will be processed

Click to select TXT/CSV files, or drag them here Select multiple files at once. Conversion runs in your browser

Sample Data

Single conversion uses the current direction. With “Auto Detect”, numbers and Roman numerals can be mixed.

Conversion Result

Total0

Success0

Error0

Files0

#	Input	Direction	Result	Status

Roman Numeral Chart

X10

L50

C100

D500

M1000

MMMCMXCIX3999

I, X, and C can be used in subtractive pairs: IV, IX, XL, XC, CD, CM.
V, L, and D are not repeated; I, X, C, and M are usually not repeated more than three times.
The standard range is 1 to 3999. Values outside it will show an error.

Validation Tips

Strict mode rejects nonstandard forms like IC, IIII, VX, and MCMC.
Loose mode can parse some nonstandard forms and return the standard form or value.
CSV/TXT files are read using the selected delimiter; empty items are ignored.
Multiple exports are packed as a ZIP; duplicate names get numbers appended.

Instructions

Software Usage Instructions

Set conversion rules: Choose single conversion or batch conversion, then select Arabic numerals to Roman numerals, Roman numerals to Arabic numerals, or auto-detection.
Configure validation options: You can enable strict validation, automatically normalize letter case and common Roman symbols, and set the batch delimiter method, export format, and number of preview rows.
Enter content to convert: For single conversion, you can enter the number directly; for batch conversion, you can paste multiple lines of content or select a TXT or CSV file.
Use sample data: Click the sample button to load Arabic numeral, Roman numeral, or mixed examples, making it easy to quickly view the conversion results.
Start conversion: Click “Start Conversion” or “Start Batch Conversion,” and the system will display the number of successes, number of errors, and a results preview.
Copy or download results: Single results can be copied with one click; batch results can be copied as text, file results can be exported using the original file name, and multiple results will be packaged as a ZIP.

FAQ

A: Standard Roman numeral notation from 1 to 3999 is supported. Numbers beyond this range require extended notation such as overlines; this tool handles the commonly used standard range.

A: Strict validation rejects non-standard forms such as IC, IIII, and VX, and suggests a more standard Roman numeral form. It is suitable for formal documents and teaching scenarios.

A: When batch content contains both Arabic numerals and Roman numerals, you can choose auto-detection. The tool will determine each input type individually and convert it to the other numeral format.

A: Line breaks, commas, spaces, and other separators are supported. You can also specify in the settings to split by line, comma, or space, making it easier to process content copied from tables.

A: TXT and CSV text files are supported. The file can contain one number per line, or multiple numbers separated according to the configured delimiter. UTF-8 encoding is recommended.

A: File conversion results use the original file name by default. If multiple files have the same name, a number will be appended to the file name to distinguish them. Multiple results will be packaged as a ZIP for download.

Roman Numeral Converter

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Tool Usage

Instructions

Software Usage Instructions

FAQ

Q: What number range is supported?

Q: What does strict validation do?

Q: When is auto-detection mode useful?

Q: What delimiters can be used for batch input?

Q: What format requirements are there for uploaded files?

Q: How will result files be named?

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