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ASCII Validator

Validate if your text contains only ASCII characters. Instantly detect non-ASCII characters, find their positions, and get detailed character analysis.

Total Characters
ASCII Characters
Non-ASCII Characters
ASCII Percentage

Non-ASCII Characters Found

Position Character Unicode Hex Code

Showing first 100 non-ASCII characters. Total found:

🔍

Enter text above to validate for ASCII characters

💡 How to Use This Tool

Validate your text for ASCII compliance in seconds. Follow these simple steps:

1

Enter Your Text

Paste or type the text you want to validate in the input area.

2

Choose ASCII Mode

Enable "Extended ASCII" if you need to allow characters 128-255.

3

View Results

See instant validation results with character statistics.

4

Review Non-ASCII

If found, view detailed info about each non-ASCII character.

📖 About ASCII Validator

What is ASCII Validator?

ASCII Validator is a free online tool that checks whether your text contains only ASCII characters (codes 0-127). It helps identify non-ASCII characters like accented letters, emojis, and special Unicode symbols that may cause compatibility issues in certain systems.

Common Use Cases

  • Data Validation: Ensure user input contains only ASCII characters for legacy systems
  • File Processing: Check configuration files, CSV data, or logs for encoding issues
  • Code Review: Verify source code doesn't contain invisible Unicode characters
  • API Integration: Validate data before sending to ASCII-only APIs
  • Database Migration: Identify problematic characters before importing data
  • Email Verification: Check email addresses for non-ASCII characters

Key Features

Instant Validation

Get immediate feedback on whether your text is 100% ASCII compliant with a clear pass/fail indicator.

Non-ASCII Character Detection

Automatically identifies all non-ASCII characters in your text with their exact positions and Unicode code points.

Character Statistics

View detailed statistics including total characters, ASCII characters, non-ASCII characters, and percentage breakdown.

Extended ASCII Mode

Option to allow extended ASCII characters (codes 128-255) for systems that support them.

Privacy First

All validation happens locally in your browser. Your text is never sent to any server.

Technical Details

ASCII (American Standard Code for Information Interchange) defines 128 characters (0-127) including control characters, digits, letters, and basic punctuation. Extended ASCII (128-255) adds additional characters but varies by encoding. This tool uses JavaScript's charCodeAt() method to analyze each character's Unicode code point.

❓ Frequently Asked Questions

Yes! All processing happens locally in your browser. Your text never leaves your device.
Standard ASCII includes characters with codes 0-127 (basic Latin letters, digits, punctuation). Extended ASCII (128-255) includes additional characters like accented letters and special symbols, but varies by encoding system.
Many legacy systems, APIs, and file formats only support ASCII characters. Non-ASCII characters can cause encoding errors, display issues, or data corruption in these systems.
No, emojis are Unicode characters with code points far beyond the ASCII range. They will be detected as non-ASCII characters by this validator.
Common non-ASCII characters include accented letters (é, ñ, ü), currency symbols (€, £, ¥), typographic quotes (""), em dashes (—), and special punctuation (…).

Version History

1.0.0

Initial release

Jan 24, 2026