Choose PDF compression for an upload limit

A portal's file limit is a requirement for the final download, not a promise a compression tool can always meet. A PDF with several large photographs behaves differently from a small text document. Check the exact limit and whether the portal expects KB or MB, then retain the original before trying changes.

Start with the mode that keeps document features

1. Open Compress PDF and choose your document.
2. Enter a target and choose the matching unit. Leave Allow image-based compression unchecked for the first attempt.
3. Run compression and read the actual output size. The result may remain above the target.
4. Download and reopen the PDF. Check all required pages, searchable text, forms and links.

The default structural mode optimizes how the PDF is stored while retaining text, links and form fields. It does not promise a fixed percentage reduction. An already optimized document may offer little or no saving; the tool keeps the original when the alternative is not smaller.

Try an example that is already small

Download the original three-page sample assignment and note its size in your device's file manager. Try structural compression. This is a simple text/vector file, so a dramatic reduction is not expected. A retained original is a useful result when further processing would only enlarge it.

Understand the image-based tradeoff

If structural compression misses the limit, the optional image mode renders pages into JPEG images. This may help a large scanned document, but it changes the output fundamentally:

• Text is no longer searchable or selectable as ordinary PDF text.
• Links and interactive forms are lost.
• Accessibility tags are not retained.
• Small letters and diagrams may become blurry at stronger compression.

Use this mode only when those losses are acceptable for the recipient. Check the feature-loss disclosure before enabling it. A completed export still does not guarantee the requested size. Inspect the actual download, especially its smallest text, rather than relying on a saving percentage.

When the target remains impossible

• If the portal permits separate uploads, split the document into logical sections.
• If unnecessary pages can be omitted under the submission rules, remove them before retrying. Do not remove required pages merely to fit a limit.
• For photo-heavy documents, use clearer, smaller source images and avoid excessive empty borders when creating the PDF.
• If readability would suffer, ask the recipient for an alternative submission method.

Final checks

Open the final file independently, confirm its size and page count, and inspect signatures, diagrams and filled fields. Keep the original. These steps matter more than hitting an attractive compression percentage. The browser processes this tool's files locally; a phone can still run out of memory with a large document.