PDF files can get surprisingly large. A ten-page report with a few photos might weigh 25 MB. A presentation exported as a PDF often comes in even heavier. Most email providers cap attachments at 10 to 25 MB, many upload portals have strict size limits, and large files are simply slower to open and share. Reducing the file size fixes all of these problems — and in most cases, the document looks identical before and after.
The fastest way to reduce a PDF's file size
Filero's free Compress PDF tool uses Ghostscript — the same compression engine used in Adobe Acrobat — to reduce PDF file sizes by 40 to 80 percent. It takes about 10 seconds and requires no account or software.
- Open the Compress PDF tool.
- Upload your PDF — drag and drop or click to browse.
- Choose a quality preset: Small, Balanced, or High quality.
- Click Compress and wait a few seconds.
- The tool shows you the new file size and the percentage saved before you download.
- Download your compressed PDF.
How much smaller will my PDF get?
It depends heavily on what is in the PDF:
- Photo-heavy PDFs and presentations: These see the biggest reductions — typically 60 to 80 percent with the Balanced or Small preset. A 30 MB presentation might compress to 4 MB.
- Scanned documents: Each page is essentially a photograph, so compression works very well here too. A 20 MB scanned contract often compresses to 2 to 4 MB.
- Mixed documents (text + some images): Moderate reduction, typically 30 to 60 percent.
- Text-only documents: Limited reduction, typically 10 to 20 percent, because there is little image data to compress.
Understanding the quality presets
- Small file (72 DPI): Most aggressive compression. Images are reduced to screen resolution — enough for any monitor or phone, but not ideal for printing. Best for email attachments and online form uploads. Typical reduction: 70–85%.
- Balanced (150 DPI): Best for most everyday uses. Images look great on screen and print acceptably. Typical reduction: 50–70%. Start with this preset.
- High quality (300 DPI): For documents that will be professionally printed. Less aggressive but still meaningfully smaller. Typical reduction: 20–40%.
Other ways to reduce a PDF's file size
Besides running through a compressor, there are a few other strategies worth knowing:
- Remove unnecessary pages. If the PDF contains pages you do not need — blank pages, cover sheets, appendices — removing them reduces the size. Use Filero's Split PDF tool to extract only the pages you need.
- Compress images before creating the PDF. If you are generating the PDF yourself from a Word document or design file, compress the embedded images first using Filero's Image Compressor before export. This produces a smaller PDF from the start.
- Export at lower resolution from the source app. When saving a PDF from Word, PowerPoint, or a design tool, look for a "Minimum size" or "Web" export option rather than the default "Standard" or "Print quality" setting.
- Avoid repeated compressions. Compressing an already-compressed PDF produces diminishing returns. Run the original through the compressor once at the right preset rather than compressing multiple times.
Does reducing PDF file size affect text quality?
No. Text in a PDF is stored as vector data, not as a raster image. Compression only affects rasterised images embedded in the document. Text remains perfectly sharp and searchable at any zoom level, regardless of which compression preset you choose. You can still copy and paste text, search within the document, and print at full quality.
Frequently asked questions
Why is my PDF so large in the first place?
The most common causes are embedded high-resolution images (especially in presentations and scanned documents), fonts embedded at full fidelity, and redundant data left by PDF creation software. Compression removes the image data that exceeds what a screen needs to display the document clearly.
Can I reduce a PDF file size on my phone?
Yes. The Compress PDF tool works in any mobile browser. Open it in Safari or Chrome on your iPhone or Android, upload your file, choose a preset, and download the compressed result. The whole process takes under a minute.
What is the maximum file size the tool accepts?
Filero's Compress PDF tool accepts files up to 100 MB. If your PDF is larger than this, use the Split PDF tool to divide it into sections, compress each section, then merge them back together using the Merge PDF tool.
Ready to try it?
Use Filero's free Compress PDF tool. No account needed, works on any device.
Open Compress PDF