When an online form rejects your PDF because it's too large, check the exact size limit first, then compress the file with a lower quality setting. If that still isn't enough, split the document or keep only the pages you're asked for. In most cases, the file is ready to upload again within a few minutes.
Here's how to do it step by step, without ending up with a document nobody can read.
Why does the portal reject your PDF?
Online portals (job applications, insurance claims, government services, rental files) almost always cap the size of the files you upload. The limit can apply to each file, or to all your attachments combined, and it varies from one site to another.
What makes a PDF heavy is rarely the number of pages. It's mostly the images inside it: a page scanned or photographed in high resolution and in full colour can weigh more than a twenty-page text document. That's why a two-page scan of an ID or a payslip is so often the file that gets refused.
Step 1: check the limit and the real size of your file
Start by finding the exact limit. It's usually shown next to the upload button, in the instructions of the form, or in the error message itself. Note the unit: 2 MB is about 2,000 KB, and some portals count in KB.
Then check the actual size of your PDF. On Windows, right-click the file and choose Properties. On a Mac, select it and choose Get Info. Leave yourself a little margin below the limit rather than aiming for the exact figure.
Step 2: compress the PDF
Upload the file to the PDF compressor and choose the quality you want for the final document. Start with a balanced setting, download the result and compare its size to the limit.
If it's still too large, compress the original again with a lower quality setting. Always start from the original rather than from a file you've already compressed: compressing the same file twice gains little and degrades the images further.
Before you go any further, open the compressed file and zoom in on the details that matter: small print, figures, signatures, stamps. A file that fits the limit but can't be read will be rejected at the next stage.
Step 3: if the file is still too large
Some documents stay heavy even after compression, especially long scans. Three options remain:
- Split the document. If the portal accepts several attachments,
- Keep only the pages you're asked for. A portal that requests "the last three payslips" doesn't need the cover page or the blank back of each sheet. Removing them often brings the file under the limit on its own.
- Rescan with lighter settings. For text documents, a scan in black and white or greyscale at a standard resolution is enough, and much lighter than a colour photo. You can redo a page with the
Step 4: check the file before uploading it again
- Open the PDF and go through every page: nothing should be missing or upside down.
- Zoom to 100% and check that numbers, names and dates are readable.
- Make sure the file is in PDF format and not an image, if that's what the portal asks for.
- Give it a clear name (for example "payslip-september.pdf"): it helps the person who will process your file.
Why is a scanned PDF so heavy?
A scanner or a phone camera records every detail of the page, including the paper texture and shadows, often in colour and at a high resolution. The result is an image, not text, and images take up far more space.
To avoid the problem next time, scan text documents in black and white or greyscale, frame the page tightly so there's no background around it, and combine the pages into a single PDF only once each one is clean. If a form only accepts PDFs and you start from a photo, our guide on how to turn a photo into a PDF covers the conversion step.
In short
When a PDF is too large to upload, check the exact limit and the file's real size, compress it with a lower quality setting, then split it or remove unneeded pages if necessary. Before uploading it again, make sure every page is still readable.
Frequently asked questions
How do I check the size of a PDF?
On Windows, right-click the file and choose Properties. On a Mac, select it and choose Get Info. The size is shown in KB or MB: compare it with the limit stated on the portal.
Why is my PDF still too large after compression?
Usually because it contains high-resolution scans or photos. Try a lower quality setting starting from the original file, remove pages you don't need, or split the document if the portal accepts several files.
Does compressing a PDF make it harder to read?
It can, if the quality setting is too low. Always open the compressed file and zoom in on small print, figures and signatures before uploading it.
Can I upload several smaller files instead of one large one?
Only if the portal allows several attachments. Check the instructions first; if it does, split the PDF into logical parts and name each file clearly.
Why is a one-page scan heavier than a long text document?
A scanned page is an image: every pixel is stored, often in colour. A text document only stores characters, which take up very little space. Scanning in black and white or greyscale makes the file much lighter.