PDFs are fantastic for sharing, but they can sometimes become enormous, making them difficult to email or upload. A file that's too large can be a major roadblock. Fortunately, you can often reduce a PDF's file size significantly without making it look blurry or unprofessional.
This guide will cover why PDFs get so large and what you can do about it.
Why Do PDFs Get So Big?
The most common culprits for large PDF file sizes are:
- High-Resolution Images: This is the number one cause. A PDF packed with high-quality, uncompressed photos will be huge.
- Embedded Fonts: To ensure a document looks the same everywhere, PDFs can embed entire font files. If you use several different fonts, this adds up.
- Lots of Pages: Naturally, a 100-page document will be larger than a 2-page one.
- Vector Graphics: Complex illustrations and vector graphics can contain a lot of data.
How to Reduce PDF File Size
Knowing how to shrink a file is a valuable skill, and Docento.app now includes a free, private way to do it. Here are the best methods, from easiest to most advanced.
Method 1: Use Our Free Compress PDF Tool
The fastest way to shrink a PDF is our built-in Compress PDF tool. Unlike most online compressors, it runs entirely in your browser, so your file is never uploaded to a server.
Here's how it works:
- Open the Compress PDF tool and drop in your file.
- Choose a compression level: Light, Recommended, or Strong.
- Download the newly shrunk PDF, with your text still selectable.
It recompresses the images inside your PDF while leaving text intact, often reducing file size by 50-90% on image-heavy documents. For a step-by-step walkthrough, see how to compress a PDF online.
Method 2: The "Print to PDF" Trick
This is a clever workaround that can sometimes help. It works by "re-printing" your PDF into a new, cleaner file.
- Open your PDF in your web browser or a PDF reader like Adobe Reader.
- Go to File > Print.
- In the printer destination dropdown, select "Save as PDF" or "Microsoft Print to PDF".
- Save the new file.
This process can sometimes strip out unnecessary data and flatten a file, resulting in a smaller size.
Method 3: Optimize Images Before Creating the PDF
If you are creating the PDF yourself (e.g., from a Word document), the best strategy is to optimize your images before you save the file as a PDF.
- Resize Images: Don't insert a massive 4000-pixel-wide photo if it's only going to appear as a small thumbnail. Resize it to the approximate dimensions you need first.
- Compress Images: Use a tool like TinyPNG or an image editor to compress your JPGs and PNGs before adding them to your document.
When to Keep the File Size High
Sometimes, you need high quality. If you're sending a document to a professional printer, they will require a high-resolution PDF to ensure the final product is crisp and clear. In that case, don't compress it. But for emailing, web viewing, or general sharing, a smaller file is always better.
