How to Check the DPI of a PDF?

DPI (dots per inch) determines the resolution of images in your file. In this guide, we’ll explain how to find DPI of PDF files, what to do if the info’s missing, and how to adjust DPI when needed.

What Is DPI in a PDF?

DPI stands for dots per inch, a measurement of image resolution. The higher the DPI, the clearer and sharper your images will appear, especially when printed.

In PDFs, DPI usually applies to scanned pages or embedded images, not text. So if you want to check DPI on PDF files, you’re likely inspecting a scan, photo, or design element.

How to Check DPI in a PDF?

There’s no DPI label inside a PDF by default. But here’s how to check the DPI of a PDF using fast, free methods.

1. Convert the PDF to Image and Check Resolution

• Go to PDF to JPG
• Upload your PDF and convert it into an image file
• Download the JPG or PNG version

• Right-click the image > Properties > Details (Windows)
• Look for Horizontal and Vertical DPI

This is one of the most accurate ways to check DPI of PDF content.

2. Use Preview or Built-In Tools (Mac)

• Open the PDF in Preview
• Use the Selection Tool to inspect an image or scanned section
• Click Tools > Show Inspector > Info
• DPI will appear in the image metadata

This method helps you see DPI of PDF files without third-party apps.

3. Use a PDF Reader with Metadata Access

• Go to PDF Reader
• Upload your file
• While not all readers show DPI directly, you can assess quality by zooming in on images — if it pixelates quickly, it may be low DPI

What to Do If You Can’t Find the DPI

Sometimes, DPI data isn’t embedded in the file. Here's how to tell DPI of PDF content when metadata is missing:

• Zoom in to see how fast images blur
• Check if the file was created from a scan — many scanners default to 150–300 DPI
• Use the conversion method above to measure manually
• If working with clients, ask for original source files to verify image resolution

DPI is only one part of quality — visual clarity also depends on compression and file format.

How to Adjust DPI in a PDF

While PDFs don’t let you “set” DPI directly, you can improve resolution with a few workarounds:

• Rescan documents at a higher DPI (300 or 600 is ideal for print)
• Convert high-resolution images to PDF using PDF to JPG
• Use image editing tools to enhance sharpness before embedding
• Avoid compressing files too much when exporting or saving

Want to upgrade a low-DPI image? Convert the page to JPG, upscale it, and then reimport it into your document using a PDF Reader or editor.

FAQs

1. Can I change the DPI of a PDF?

Not directly, but you can replace low-resolution images or rescan your document. Increasing DPI requires access to the original content.

2. Why can’t I find DPI info in some PDFs?

PDFs don’t always store DPI metadata. It depends on how the file was created — scanned files usually have it, but vector-based PDFs often don’t.

3. Does DPI affect the text quality in a PDF, or only images?

DPI only affects images and scanned content. Native text in PDFs stays sharp at any zoom level because it’s vector-based.

4. Does changing the DPI of a PDF change its file size?

Yes. Higher DPI means more image data, which increases file size, especially in scanned or photo-heavy PDFs.

5. If I zoom in on a PDF and it blurs, does that mean it has low DPI?

Usually, yes. That’s a sign the image has a low resolution. High-DPI images stay crisp even when zoomed in.