Inspect and convert any file locally. Nothing leaves your device.
Drop a file to see what it actually is — its real format from the magic bytes, whether the extension is telling the truth, cryptographic checksums, entropy, and the raw bytes themselves. Every byte is read locally in this browser tab. No uploads, no servers, no accounts.
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Drop any file to inspect it
or click to browse · paste from clipboard · drop a whole folder
Images, video, audio, archives, PDFs, documents, fonts, executables, text and data — over 80 formats identified by signature, and anything else read as raw bytes.
Convert between JPG, PNG, WebP, GIF, BMP and TIFF with full control over quality and resolution. Files are processed by your own browser, so nothing is uploaded and there are no size limits imposed by a server.
Convert video and audio with a full FFmpeg build compiled to WebAssembly, running inside your browser. Large files stay on your machine instead of being uploaded to a queue.
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Drop your video/audio files here or click to select
💡 Supports batch conversion with progress tracking
⚠️ Large files detected. Each file is limited to 2GB by browser memory. Processing will be slow.
Video/audio quality settings
23
Lower values mean higher quality and larger files.
Loading FFmpeg…
✅ Conversion complete
🎬 Supported video & audio formats
MP4: Most universal video format, excellent for web and devices
WebM: Open-source format, great for web streaming
MOV: Apple QuickTime format, high quality
AVI: Classic format with broad compatibility
MKV: Open container supporting multiple codecs
MP3: Most popular audio format, universal support
WAV: Uncompressed audio, best quality
OGG: Open-source alternative to MP3
FLAC: Lossless audio compression
AAC: High-quality audio, Apple's preferred format
💡 Pro tip: Convert large video files to WebM or MP4 with higher compression
to save storage. For audio, use MP3 for general use or FLAC for archival quality.
⚡ How Our Private File Tools Work Without Uploading
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1. Select your files
Choose any file from your device. No uploading required — files stay on your computer.
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2. Processed in your browser
Analysis and conversion run directly in your browser using WebAssembly and Web Workers.
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3. Results instantly
Reports and converted files appear immediately. No server queues. Works offline.
🔒 Why choose our private file tools?
100% private & secure: Unlike other online tools, your files never leave your device. No uploads to servers, no privacy risks.
Faster than competitors: Skip upload/download time entirely. No waiting for server processing queues.
Zero bandwidth usage: Save internet data. No uploading large files just to inspect or convert them.
Works completely offline: After loading the page once, use it without an internet connection. Perfect for sensitive documents.
Questions
❓ FAQ: Free Private File Inspector & Converter
Drop the file into the File Inspector. It reads the file's magic bytes — the signature stored in its first bytes — and reports the actual format, then compares that against the extension and the browser-reported MIME type. A renamed or disguised file is flagged as a mismatch, and you can see the exact bytes in the hex viewer.
Drop the file into the File Inspector. LocalConverter computes MD5, SHA-1, SHA-256 and CRC32 in a single streaming pass, entirely on your device. Nothing is uploaded, so it is safe to hash confidential files, and because the file is streamed in chunks it works on files up to 2GB without exhausting memory.
Entropy measures how unpredictable the bytes are, from 0 to 8 bits per byte. Plain text sits around 4; already-compressed media such as JPEG or MP4 sits above 7; encrypted or archived data approaches 8. It is a quick way to tell whether a file is already compressed — if entropy is near 8, compressing it further will not help. The entropy graph also shows how this varies across the file, which reveals headers, padding and embedded data.
Absolutely. Your files never leave your device — they're processed entirely within your browser using WebAssembly, Web Workers and Canvas. No data is transmitted to any server, stored in any database, or accessible to anyone else. You can disconnect from the internet after loading the page and everything still works.
Traditional online converters require you to upload your files to their servers, wait for processing, then download the results. This creates three bottlenecks: upload time, server processing queue, and download time. LocalConverter eliminates all upload/download time by processing files directly in your browser using your device's full processing power.
LocalConverter saves 100% of the bandwidth normally used for file conversion. A typical 50MB video file would require 100MB of bandwidth (50MB upload + 50MB download) with online converters. With LocalConverter, you use zero additional bandwidth since processing happens locally.
Inspection: over 80 formats identified by signature — images, video, audio, archives, documents, fonts, executables and data files — plus raw byte analysis for anything else. Images: JPG, PNG, WebP, GIF, BMP, TIFF, HEIC, AVIF with no size limits. Video/Audio: MP4, WebM, MOV, AVI, MKV, MP3, WAV, OGG, FLAC, AAC. Conversion is limited to 2GB per file due to browser memory constraints, but this is still larger than most online converter limits.
LocalConverter works on desktop and mobile devices with modern browsers (Chrome, Firefox, Safari, Edge). File inspection and image conversion work everywhere, while video conversion requires browsers that support WebAssembly. For best performance, use Chrome or Edge on desktop devices.
Yes. LocalConverter supports batch processing with progress tracking. Select multiple files, choose your format and settings, then convert them all at once. You can download files individually or as a ZIP archive. The inspector accepts multiple files and whole folders too.
LocalConverter is completely free with no hidden costs, subscriptions, or premium tiers. There are no watermarks added to your files, no conversion limits, and no registration required. The tool runs entirely in your browser, so there are no server costs to pass on to users.
Simply select your JPG files using our image converter, choose PNG as the output format, and click convert. The conversion happens entirely in your browser without uploading files to any server. You can convert multiple JPG files to PNG format at once using our batch processing feature.
Select your MP4 files in our secure video converter, choose WebM format, adjust quality settings if needed, and convert. Unlike other online converters, your video files are processed locally in your browser, ensuring complete privacy and security. No files are uploaded to servers.
LocalConverter is the most secure option for sensitive files because it processes everything locally in your browser. Unlike other free file converters that upload your files to servers, LocalConverter ensures your sensitive documents never leave your device. It works offline and supports batch conversion.
LocalConverter vs competitors: While tools like Online-Convert.com and FreeConvert.com require uploading files to servers, LocalConverter processes files locally. That means ✓ faster conversion (no upload/download time), ✓ complete privacy (files never leave your device), ✓ works offline, ✓ no server-imposed file size limits, ✓ zero bandwidth usage — and a full file inspector that those tools do not offer at all.
Why LocalConverter
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100% Private
All analysis and conversion happens locally in your browser. Your files never leave your device or touch our servers.
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Deep Inspection
Real file type from magic bytes, signature validation, checksums, entropy analysis and a full hex viewer.
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Lightning Fast
No upload wait times. Hashing runs in a Web Worker so the interface stays responsive on multi-gigabyte files.
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Works Offline
Once loaded, keep working without internet. Perfect for sensitive or confidential files.
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Batch Processing
Inspect whole folders and convert multiple files at once, with progress tracking and bulk download.
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Completely Free
No subscriptions, no limits, no watermarks. Professional-grade tooling at zero cost.
🌟 Why LocalConverter is the Best Free Private File Tool
🔬 See What a File Really Is
Extensions lie. LocalConverter reads the actual signature bytes to identify over 80 formats, then tells you whether the extension, the MIME type and the content agree — the same check security tools perform, running privately in your browser.
🔒 Complete Privacy & Security
Convert JPG to PNG, MP4 to WebM, and hash confidential documents without uploading anything. Your sensitive files stay on your device, making this safe for confidential business files, personal photos and private videos.
⚡ Faster Than Competitors
Skip the upload and download queues of traditional online tools. LocalConverter processes files instantly in your browser, making it faster than services like Online-Convert.com, FreeConvert.com and other server-based tools.
💰 100% Free Forever
No hidden costs, no premium subscriptions, no watermarks on converted files. Inspect and convert unlimited files with professional quality controls — completely free, no registration required.
Start now: drop a file at the top of the page to inspect it, or use the converters above. Supports 80+ formats for inspection and 15+ formats for conversion including JPG, PNG, WebP, MP4, MP3 and WebM.