How to Get a PDF Under 1 MB or 2 MB for Upload Portals

How small does each page need to be?

Divide the limit by the number of pages and subtract 10%. A 2 MB limit for a four-page document gives about 450 KB per page, which is plenty for a clear scan. A 1 MB limit for ten pages gives 90 KB per page, which is tight for scans.

The 10% headroom matters because portals do not agree on what a megabyte is. Some count 1,000,000 bytes and others 1,048,576, a difference of almost 5%, as the Megabyte article explains. macOS Finder uses the decimal unit and Windows Explorer the binary one, so the same file can show as 2.0 MB on a Mac and 1.9 MB on Windows. Aim for 1.8 MB against a 2 MB limit and the question goes away.

Text PDFs exported from Word are rarely the problem. A ten-page text document is often under 200 KB. Oversized files are nearly always scans and phone photos.

Step 1: compress with Recommended

Open Compress PDF and run the file at the default level, Recommended. It resizes photos above about 150 DPI and tidies the file structure, while text and vector graphics stay sharp and selectable. Scans and photo-heavy PDFs often shrink by 50 to 90%. The Done screen shows the size before and after, so you can compare against the portal limit immediately.

If the tool reports that the PDF is already optimized, less than 1% could be saved and the original is kept. That is common for text-only files and for scans that were already compressed. Go to the next step.

Step 2: go stronger only if needed

If you are still over, run the original again with Extreme. It renders every page as a 110 DPI image, which reaches very small sizes but means text can no longer be selected, searched or read aloud by screen readers. For a portal where a person looks at the document, that is usually acceptable. Always compress from the original. Compressing an already compressed file stacks JPEG artifacts without saving much.

Then open the result and zoom into the smallest print, the signature and any official stamp. Those are the parts an assessor needs to read. At 110 DPI, 8 pt print is near the limit of legibility. The machine-readable lines at the bottom of a passport page are usually fine, because they are printed large.

Step 3: remove weight that is not needed

• Blank pages and the backs of single-sided documents: delete them with Remove Pages.
• Pages the portal did not ask for, such as terms and conditions pages on a bank statement.
• Wide scanner borders: a dark border is image data too. Note that cropping a PDF only hides the border, so crop in the scanning app, not afterwards.
• Separate upload slots: if the portal has a slot for each document, do not merge everything into one file.
• Very long documents: if the portal accepts several files, Split PDF can divide the file into parts that each fit.

Step 4: rescan smarter

When compression cannot reach the target without ruining legibility, the source is the problem. Scan again at 150 to 200 DPI instead of 300 to 600, choose grayscale or black-and-white for text, and crop tightly to the page edges. An A4 page is 2480 × 3508 pixels at 300 DPI and 1240 × 1754 at 150 DPI, a quarter of the pixel count, and the file shrinks roughly in proportion.

Why is a scanned PDF so large?

Because every page is a full-page photograph. A color A4 scan at 300 DPI holds about 8.7 million pixels, and even as a JPEG that is 1 to 3 MB per page. The same page as real text is a few kilobytes.

Three things multiply the size: resolution, color and noise. Doubling the DPI quadruples the pixels. Color needs three channels where grayscale needs one. Paper texture, shadows and creases are detail the JPEG encoder has to store, which is why a phone photo taken on a desk in evening light is bigger than a flatbed scan of the same page. Fix those at capture time and compression has far less work to do.

Why do portals reject a PDF that is under the limit?

Usually because the file is not what the portal expects: it is password-protected, it is an image renamed to .pdf, or the file name contains characters the system does not accept. Size is only the first check.

• Renaming a JPG to .pdf: portals check the file contents. Convert properly with JPG to PDF.
• Password-protected files: many portals cannot open them. If you know the password, Unlock PDF saves a copy without it. It does not crack unknown passwords.
• File names: keep them short, with letters, numbers and hyphens only, such as passport-j-smith.pdf. Accents, slashes and very long names cause silent failures on older systems.
• Using a phone screenshot of a PDF: the resolution is too low for fine print and it is not a PDF.
• Compressing so hard that stamps and signatures blur: the file uploads, but the application is rejected later by a person.
• Damaged files: if a PDF will not open in some viewers, try Repair PDF before compressing.

When not to compress

Do not compress a digitally signed PDF, such as a certified bank statement or an e-signed contract. A digital signature covers the exact bytes of the file, so any rewrite, even a lossless one, invalidates it. Upload the original, and if it is over the limit, ask the portal's support for another route. Also avoid Extreme for documents that will be read by software, for example CVs parsed by applicant tracking systems, because image-only pages contain no text to parse.

Why compress on your device

The documents that face upload limits are the most sensitive ones people handle: passports, visas, tax returns, bank statements and medical records. Compress PDF runs in the browser, so these files are compressed on your phone or laptop and never sent to a third-party server before reaching the portal you actually intend to use. Files up to 200 MB are accepted, and the tool never returns a file larger than the one you gave it.