How to compress a PDF to a size limit
Start with the PDF you want to send and the size limit given by the recipient. Drag the file into the drop area or click to choose it. Pick a preset for 500 KB, 1 MB, 2 MB, 5 MB, or 10 MB, or enter a custom limit in KB. The tool uses decimal units, so 1 MB is 1,000,000 bytes. It aims for a result smaller than the selected limit. Check the reported output size before submitting your file to a portal.
Keep text is the default. The browser rewrites the PDF using object streams and removes document metadata. A PDF with lots of structural overhead can benefit from this pass. A PDF that already uses compressed objects or consists of large embedded scans may barely change. The result card shows the size of the text-preserving attempt so you can see what that rewrite achieved.
How to compress a PDF under 500 KB
- Choose the PDF and select Under 500 KB. The target is 500,000 bytes.
- Use Keep text if you need selectable text. The result shows whether the text-preserving attempt fit or whether the tool switched to image-based compression.
- Check the output size and preview before downloading. If the smallest result still exceeds the limit, split the PDF if the recipient allows separate files or re-export it with smaller images.
For a 1 MB limit, choose that preset and follow the same steps. If a PDF misses the limit by a few kilobytes, compare the exact byte count in your file manager. The displayed KB and MB values are rounded.
If you need to preserve text, start with the original digital document and reduce large photos before exporting. Use Compare PDF to inspect the rendered changes between the original and the smaller copy.
What happens in maximum compression
If the first pass misses the target, the browser can render each page onto a canvas and build a new PDF from JPEG images. The tool starts at about 100 DPI and 35% JPEG quality, then searches for a higher resolution and quality that fit. It checks the size of the full rebuilt PDF because fonts, document objects, and page containers also affect the final count. If the smallest available result still exceeds your target, you can see its size and download it.
An image-based PDF preserves the rendered appearance and page dimensions, but its text becomes non-selectable. Search, screen-reader access to the original text, links, and interactive forms are lost. Keep an original copy when the document has those features. The first-page preview lets you check how a page looks before downloading. Review the whole output in a PDF reader before relying on it for a submission.
Worked example for a 1 MB upload limit
Suppose a 1.8 MB four-page PDF contains scanned receipts and an application portal accepts files under 1 MB. Choose the 1 MB preset and start with Keep text. If the first pass produces 1.7 MB, the result is still too large. The tool can try image-based compression and check whether the resulting pages fit under 1 MB.
If the result is 920 KB, the file is about 49% smaller than the original and is below the limit. Zoom in on receipt dates, totals, and fine print after downloading. If the smallest result is still 1.1 MB, you can use a higher target if the recipient allows it or re-export the original source pages at a smaller size.
Common mistakes with PDFs and size limits
Check whether the recipient needs selectable text, a completed form, or a digitally signed original. Rewriting a signed PDF can invalidate its signature. You may need to compress the source before signing or ask the recipient which file types are accepted. If the document is locked, use your authorized PDF reader to save an unlocked copy before processing.
Very large page dimensions, high-resolution scans, and long files can exceed the browser's processing limits even when the PDF itself is small. For a PDF you are assembling from photos, the bulk image optimizer can help resize the photos before you create the PDF. If you need to combine separate files first, visit Merge PDF.
Frequently asked questions
Are my PDFs uploaded?
No. Processing happens in your browser. The page downloads its processing libraries from jsDelivr, and the selected PDF stays on your device.
Can I keep PDF text selectable?
Try Keep text first. When that pass fits the size limit it is used as the result. Maximum compression creates image pages, which lose selectable text.
Can this guarantee my PDF will be under 500 KB?
The result depends on the page count, dimensions, and content. If the available quality and processing limits prevent a smaller output, the tool reports that and offers the smallest result it found.
Can I compress a password-protected PDF?
Open the file using your authorized password and save an unlocked copy first. The compressor cannot open an encrypted file for you.
Why is the compressed PDF larger than my original?
An already optimized PDF can be smaller than a rewritten or image-based version. Compare the before and after sizes and keep whichever file meets your needs.