"File too large." Few messages are more frustrating when you have to send a document before a deadline. University applications, visa portals, job sites and government services often limit uploads to 2 or 5 MB, and email services refuse attachments over about 20 to 25 MB.
The good news: most heavy PDFs can be made several times smaller without any visible change.
Why is my PDF so big?
Almost always because of images:
- Scans and phone photos. A page scanned at 600 dpi in colour can weigh several megabytes on its own.
- Presentations and brochures exported with full-resolution photos.
- Merged documents that contain the same logo or font many times.
Text itself is light. A 100-page report with no images is usually under 1 MB.
The fastest way: compress the PDF
- Open Compress PDF.
- Select your file.
- Choose a level:
- Recommended for most documents.
- Extreme when you must get under a strict limit, such as 1 or 2 MB.
- Light for documents you will print and want to keep very sharp.
- Download the result. The page shows how much smaller it became.
Need an exact limit, such as 100 KB or 300 KB? Use Compress PDF to a specific size: type the limit and the file comes out just under it.
The compressor lowers the resolution of oversized images, re-encodes them efficiently and removes duplicated resources and unused fonts. Text stays sharp and selectable because it is not an image.
Typical results
| Type of document | Before | After (recommended) |
|---|---|---|
| 10-page colour scan | 18 MB | 2 to 3 MB |
| Presentation with photos | 35 MB | 4 to 6 MB |
| Text report with a few charts | 3 MB | 1 to 2 MB |
These are typical values. Your results depend on the content.
Still too big? Three more tricks
1. Split the document. Many portals accept several files. Use Split PDF to cut a long document into parts, for example one file per chapter or per supporting document.
2. Compress the photos before creating the PDF. If you build a PDF from phone pictures, run them through Compress JPG first. A phone photo of a document rarely needs more than 1 MB.
3. Scan in grayscale. For text documents, a grayscale scan at 200 to 300 dpi is perfectly readable and much lighter than a colour scan at 600 dpi.
What not to do
- Don't take a screenshot of each page to "shrink" it. The text becomes an image, is no longer searchable and often ends up blurry.
- Don't compress the same file several times at the extreme level. Each pass lowers image quality a little more.
Tip: if a portal asks for a specific limit, check the file size in your downloads before uploading. On Windows, right-click › Properties. On a Mac, select the file and press Space. On a phone, the size appears in the Files app.