File Compressor
Reduce file size online locally in your browser. Compress images, video, PDFs, and package folders into ZIP without uploading files to remote servers.
or drag & drop here
Paste from clipboard with Cmd+V · Multiple files supported
Supported: Any file
- Never uploaded
- No watermark
- No sign-up
- No server upload limits
How It Works
Simple 3-step compression powered entirely by your local browser
Add Files
Drag multi-file batches into the client workspace.
Select Smart or Target Size
Choose Balanced optimization or specify target size thresholds for your media and documents.
Save Instant ZIP
Pure client-side streaming ZIP packaging without server limits, data storage, or network bottlenecks.
Why Choose LessMB
The private, modern alternative to legacy cloud compressor websites
100% In-Browser Privacy
Zero bytes uploaded. Your personal photos, sensitive documents, and private videos never touch external servers or cloud storage.
Zero Queue & Instant Start
No waiting in cloud conversion queues or watching slow upload bars. Processing starts the millisecond you drop your file.
Hardware Acceleration
Harnesses WebAssembly SIMD and WebCodecs GPU encoding for high-fidelity compression directly on modern consumer hardware.
No Credit Consumption
Free tier compression uses your own device compute, meaning zero server credit drain for everyday single and batch tasks.
LessMB vs Traditional Cloud Compressors
See how client-side processing outperforms legacy server-based tools
Multi-Format Local Compression & Ratio Benchmark
Processed locally in browser memory without server uploads. The matrix below details real savings across common file types under Balanced mode.
| Category | Input Format | Original Size | Compressed | Saving | Target Platform & Constraint |
|---|---|---|---|---|---|
| Photos | JPG / HEIC | 8.4 MB | 1.2 MB | ~85% | Email attachments, web publishing |
| Graphics | PNG (24-bit) | 3.6 MB | 680 KB | ~81% | Alpha transparency preserved, UI assets |
| Video Clip | 1080p MP4 / MOV | 58.0 MB | 7.8 MB | ~86% | Discord Free 10MB limit, email sharing |
| Scanned PDF | PDF (300 DPI) | 14.2 MB | 1.9 MB | ~86% | Job boards, government portal 2MB cap |
| Multi-Files | Mixed / Folder | 42.0 MB | 18.5 MB | ~56% | Fast local ZIP archive, zero privacy leak |
ZIP Deflate vs. Smart Media Re-encoding: Why Plain Archives Fail on Media
Archiving files into a .zip container relies on lossless byte-level dictionaries (Deflate/LZ77). Because JPEG, PNG, and MP4 streams are already high-entropy compressed data, plain ZIP archives only reduce file weight by 1% to 3%. LessMB inspects codecs and applies perceptual re-encoding locally.
Platform Upload Limits & Target Size Solutions
Popular messaging tools enforce 20MB to 25MB limits. Set a 24MB target in LessMB for videos or PDFs to ensure instant inline playback.
Official submission portals require attachments under 2MB. Downsample 300 DPI flatbed scans while keeping vector text crisp and selectable.
Mail gateways reject attachments over 20MB. Balanced compression safely shrinks 50MB multi-page decks to 5-8MB for inline preview.
Frequently Asked Questions
Everything you need to know about LessMB in-browser compression
Tutorials & Guides
Deep dives from the LessMB editorial team
How to Reduce File Size in MB Without Losing Quality
Why files balloon into dozens of megabytes, when lossless passes work, when downsampling is mandatory, and how to hit exact MB caps without visible degradation.
Read guide
How to Compress Images to an Exact File Size
Set a target KB or MB size, understand why files miss hard limits, and use a browser-local workflow to verify the final output before upload.
Read guide
How to compress a video to 8MB, 10MB, or 25MB
Calculate the exact bitrate required to fit MP4 and MOV videos under platform upload caps for Discord, email, and messaging apps without visible blur.
Read guideLooking for other file formats? Back to LessMB Free Online File Compressor