Free Online GZIP Compression Checker - Test and Validate GZIP Files
Free online tool to check, test, and validate GZIP compressed files. View compression ratio, headers, and metadata instantly.
How to Check GZIP Compression - Complete Validation Guide
Upload Your GZIP File
Start by uploading the GZIP file you want to check and validate. This tool accepts .gz files and base64-encoded GZIP data:
Example: GZIP File Input
Here's what a GZIP file looks like in base64 format (first 100 characters):
H4sIAAAAAAAAA5WRT0sDMRDF7/0UQ86r7C4Wul7V7kVlsdWLlJDdna7B/ClJtlJKv7uTiBUp...The tool will validate this is a proper GZIP file and extract its metadata.
View GZIP Analysis Results
The tool automatically validates and analyzes your GZIP file, providing detailed information:
Example: GZIP Analysis Output
Here's what the analysis shows for a typical GZIP file:
All this information is extracted from the GZIP header!
Preview Decompressed Content
View the decompressed content and save it if needed:
Frequently Asked Questions
How do I check if a file is GZIP compressed?
Upload your file using the "Upload" button or paste its base64-encoded content. The tool will instantly check for the GZIP magic number (1f 8b) and validate the file format. If it's valid GZIP, you'll see a green "Valid GZIP" badge with detailed analysis information.
What information can I see about a GZIP file?
The tool extracts and displays: compression method (usually DEFLATE), compressed and original file sizes, compression ratio percentage, modification timestamp, operating system used to create the file, GZIP flags, and original filename if stored in the header.
How is the compression ratio calculated?
The compression ratio shows how much smaller the compressed file is compared to the original. It's calculated as: (1 - compressed_size / original_size) × 100%. For example, if a 10KB file is compressed to 2KB, the ratio is 80% (the file is 80% smaller).
Is it safe to check GZIP files online?
Absolutely. All file validation and analysis happens entirely in your web browser using JavaScript. Your files never get uploaded to any server, ensuring complete privacy and security for sensitive data.
What does "Invalid GZIP format" mean?
This error means the file doesn't have a valid GZIP header. GZIP files must start with the magic number bytes 1f 8b (hex). The file might be corrupted, not actually GZIP compressed, or encoded incorrectly. Try re-downloading or re-compressing the original file.
Can I check GZIP compression on Windows, Mac, or Linux?
Yes! This is a web-based tool that works on any platform with a modern browser. On the command line, you can use file filename.gz on Unix systems or gzip -t filename.gz to test GZIP files.
What's the difference between GZIP and ZIP?
GZIP typically compresses a single file using the DEFLATE algorithm, while ZIP is an archive format that can contain multiple files and directories. GZIP is commonly used in Unix/Linux systems and web servers, while ZIP is more common in Windows environments.
Can this tool check TAR.GZ files?
Yes! TAR.GZ files are TAR archives compressed with GZIP. This tool will validate the GZIP layer and show you the compressed TAR data. For full TAR.GZ extraction, use our TAR.GZ Extractor tool.
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