File Size AnalyzerAnalyze file size with unit conversions and transfer time estimates.

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File Size Analyzer

Analyze file size with unit conversions and transfer time estimates.

How to Use

Upload any file

Drop or select any file to analyze.

View size breakdown

See file size in bytes, KB, MB, and GB.

Check transfer times

View estimated transfer times for various connection speeds.

What Is File Size Analyzer?

File Size Analyzer provides detailed file size information and estimated transfer times. Upload any file to see its size in multiple units (bytes, KB, MB, GB), MIME type, and last modified date. The tool also calculates estimated transfer times for common connection speeds including 3G, 4G, 5G, WiFi, broadband, and gigabit connections. This helps you understand how long file uploads or downloads will take on different networks.

Why Use Our File Size Analyzer?

Size breakdown in bytes, KB, MB, and GB simultaneously.
Transfer time estimates for 6 connection speeds.
MIME type and last modified date displayed.
No file upload — analysis happens instantly in your browser.

Common Use Cases

Web Optimization

Check file sizes for web assets to optimize page load times.

Email Attachments

Verify file sizes before attaching to emails with size limits.

Transfer Planning

Estimate download or upload times for large files on different connections.

Storage Planning

Check file sizes when planning storage capacity needs.

Technical Guide

The analyzer uses the File API's metadata properties: name, size, type, and lastModified. No file content is read — only metadata is accessed, making the analysis instant. Size conversions use binary units (1 KB = 1024 bytes) which matches how operating systems report file sizes. Transfer time calculations use: time = (file_size_bits) / (connection_speed_bps). Connection speeds used: 3G (1 Mbps), 4G (10 Mbps), 5G (100 Mbps), WiFi (50 Mbps), Broadband (100 Mbps), Gigabit (1 Gbps). Times are formatted in appropriate units (ms, seconds, minutes, hours).

Tips & Best Practices

1
File metadata is read instantly — no file content is processed.
2
Transfer times are theoretical maximums — real speeds may vary due to overhead.
3
KB/MB/GB use binary units (1024-based) matching OS file size reporting.
4
Compare transfer times across speeds to choose the right connection for large transfers.

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Frequently Asked Questions

QIs the file actually uploaded?

No, only file metadata (name, size, type) is read. The file content is not processed.

QAre the transfer times accurate?

They are theoretical estimates based on connection speed. Real-world transfers include overhead and may be slower.

QWhat units are used for KB/MB?

Binary units: 1 KB = 1024 bytes, 1 MB = 1048576 bytes.

QCan I analyze multiple files?

Currently one file at a time. Upload a new file to replace the current analysis.

QWhy is the MIME type "unknown"?

Some file types may not have a MIME type recognized by the browser. The extension can help identify the format.

About File Size Analyzer

File Size Analyzer is a free online tool from FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration required. No ads. Just fast, reliable tools.