Compress PDF Online Free – Reduce PDF File Size

🛡️Files stay on your device

⚡Instant processing

🚫No watermarks

📋No sign-up

🗜️

Drag & Drop Your PDF Here

Upload a PDF to reduce its file size

📂 Select PDF File

⚙️ Compression Level

Level

⚠️ Browser-based compression works by stripping metadata and resampling images. For maximum compression of text-heavy PDFs, results may be modest. Image-heavy PDFs see the most reduction.

Compressing…

✅

PDF Compressed!

File size reduced.

HOW IT WORKS

Compress a PDF in 3 Steps

Upload PDF

Select or drag the PDF you want to make smaller.

Choose Level

Pick Low, Medium, or High compression based on your quality vs. size preference.

Download

See the size reduction and download your compressed PDF instantly.

Free Online PDF Compressor — How It Works

PDFScanner's compression tool uses pdf-lib to rebuild your PDF with optimized settings: metadata is stripped, object streams are compressed, and embedded images are resampled at reduced quality depending on your chosen level. This works best for PDFs that contain large images such as scanned documents, brochures, or photo-heavy reports.

Honest Limitations of Browser-Based Compression

It's important to be transparent: browser-based PDF compression has limitations compared to server-side tools like Ghostscript. For PDFs that are primarily text, the size reduction will be modest (5-15%). For image-heavy PDFs, reductions of 30-70% are achievable. If maximum compression is critical, consider using our tool for a first pass and then running through a dedicated desktop tool.

FAQ

Compress PDF — FAQ

How much will the PDF size be reduced?▼

It depends on the PDF content. Image-heavy PDFs can be reduced by 30-70%. Text-only PDFs may see 5-15% reduction. The compression level you choose also affects the result.

Will compression affect text quality or readability?▼

Text in PDFs is vector-based and is not affected by compression. Only embedded raster images are resampled at lower quality on High compression settings.

Why is my compressed file the same size or larger?▼

This can happen with PDFs that are already highly optimized, contain minimal images, or use specialized compression internally. In these cases, pdf-lib's rebuilding process may produce similar or slightly larger output.