PDF Compressor

Compress PDF files online and reduce size without losing text sharpness. Browser-local PDF compression keeping vector text crisp, zero uploads.

100% Local · Files Never Leave Your Device

Compression Mode

or drag & drop here

Paste from clipboard with Cmd+V · Multiple files supported

Supported: PDF

No server upload limit0 KB uploadNo watermark100% Free

Processing happens locally in your browser — nothing is uploaded.

Try a sample:

Never uploaded
No watermark
No sign-up
No server upload limits

How It Works

Simple 3-step compression powered entirely by your local browser

§ 01

Step 01

Add Your PDF

Select or drop your document. It opens locally — there is no upload step at all.

§ 02

Step 02

Optimize the Structure & Embedded Images

The engine cleans document structure and, depending on the selected mode, may recompress large embedded images without rasterizing the whole page.

§ 03

Step 03

Save the Smaller PDF

Download the result when processing completes. Vector text is kept as vector content while embedded images may change with stronger modes.

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

Feature

Cloud Compressors

LessMB

Data Privacy

Files uploaded to 3rd-party servers

100% In-Browser (0 bytes uploaded)

Upload Latency

Minutes spent uploading large files

Instant (0s upload time)

Queue Wait Time

Enqueued during peak hours

Immediate local execution

Credit Limits

Depletes daily or monthly credits

No credit deductions for local compute

Target Size Accuracy

Rough percentage estimates

Dual-pass KB / MB target limits

Folder Tree Packaging

Rarely supported

Full folder hierarchy preserved in ZIP

Category Leaf Tools

Specialized Tools & Guides

Purpose-built browser tools solving specific format and platform constraints.

How to Compress a PDF on Mac

Learn how to compress a PDF on Mac with Preview or a local browser tool. Follow export steps, compare methods, and check text and images before sharing.

Launch Tool

Frequently Asked Questions

Everything you need to know about LessMB in-browser compression

Tutorials & Guides

Deep dives from the LessMB editorial team

How to Compress a PDF Online Without Guesswork

See how PDF structure cleanup and image recompression affect file size, when stronger modes may reduce image quality, and how to choose the right mode.

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

Looking for other file formats? Back to LessMB Free Online File Compressor