How to reduce a PDF file size to a target KB or under 1 MB
Upload portals often limit PDFs to sizes like 200 KB, 500 KB or 1 MB. A PDF gets big when it holds high-resolution images, and scanned documents are the worst case because every page is a photo.
How to compress
- Choose your PDF in the compressor below.
- Enter the maximum size in KB.
- Select Compress PDF and download the result.
What this tool does
It rebuilds each page as an image and lowers the image quality until the file fits your target. That reliably shrinks scans and image-heavy files. The trade-off is that text in the result is no longer selectable or searchable, because each page becomes a picture. Keep the original if you need to copy text from it.
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- Re-export from the original app (Word, Docs) with a “reduced size” or “minimum size” option, which keeps text as text.
- Scan at 150 to 200 DPI instead of 300 or 600 for documents that are only read on screen.
- Split a long document and upload the parts separately if the portal allows.
Privacy
The file is processed in your browser, so a passport scan or ID document is not uploaded to a server.
Set your target size in the compressor below.
Why PDFs get so large
A PDF is a container. Text, fonts and vector shapes are tiny, but images are heavy. A scanned page is usually one big image, so a 20-page scan at 300 DPI can reach 10 to 30 MB. Embedded fonts, uncompressed images and photos pasted at full resolution add to the total.
Common upload limits
| Where | Typical limit |
|---|---|
| Government and exam portals | 100 KB to 2 MB, set per form |
| Job application sites | 1 MB to 5 MB |
| Gmail attachments | 25 MB total |
| Outlook.com attachments | 20 MB |
Limits change, so read your portal's instructions.
Step-by-step: compress a PDF to a target size
- Open the compressor and choose the PDF.
- Enter the target in KB, for example 500 or 1000 for 1 MB.
- Compress and download.
- Open the result and check every page is readable, especially small print and stamps.
What the tool changes
To reach a target reliably, each page is rendered as an image and the image quality is lowered until the file fits. The result is dependable for scans and photo-heavy documents. Pages become pictures, so you cannot select or search the text. If a portal requires searchable text, use another method.
Methods that keep text searchable
- Re-export from the source. In Word or Google Docs choose Save as PDF with the "minimum size" or "reduced size" option.
- Compress images before inserting them into the document.
- Rescan at 150 to 200 DPI in greyscale or black and white. Many documents read well at that level.
- Remove unused items such as hidden layers, attachments and large embedded fonts in a PDF editor.
Choosing a scan resolution
| DPI | Best for |
|---|---|
| 100 to 150 | Reading on screen, small uploads |
| 200 | General documents with small print |
| 300 | Printing, OCR and fine detail |
| 600 | Archival, rarely needed |
Large file still over the limit?
- Split the PDF into two files and upload each part, if the portal allows.
- Remove blank or duplicate pages.
- Use black and white for text-only pages.
- Raise the target a little if the result is hard to read.
Checking the result
Zoom to 100% and read the smallest text, the signature, dates and numbers. A document that is too blurry can be rejected even if it meets the size limit.
Privacy
The compression runs in your browser. Your passport, certificates and statements are not uploaded or stored by this site.
Troubleshooting: common problems and fixes
- The PDF is still too large. Lower the target, remove pages or scan at a lower resolution.
- Text is blurry after compression. The target is too small. Raise it or use re-export from the source file.
- The tool cannot open the file. The PDF may be password protected or damaged. Remove the password first.
- The portal says invalid PDF. Some portals need a specific PDF version. Re-save with Print to PDF.
- I need searchable text. Use the original app’s reduced size export instead of rasterising.
Is PDF compression private?
The PDF is processed in your browser. It is not uploaded, stored or shared. Always check the final file before you submit it, especially for small text, stamps and signatures.
More free Zyphub tools you may need
- PDF Compressor: Shrink a PDF to a KB or MB limit.
- PDF Merger: Combine PDFs into one.
- Exact KB Image Compressor: Compress an image to an exact KB size.
Frequently asked questions
How do I reduce a PDF to 200 KB?
Choose the file, set 200 as the maximum size in KB and compress. For scans, this lowers the image quality until the file fits.
Why is my PDF so big?
Usually because of high-resolution images or scanned pages, since each scanned page is a photo.
Will text still be searchable after compression?
Not with this tool, because it turns pages into images. To keep text, re-export from the original app with a smaller size option.
What scan resolution should I use?
150 to 200 DPI is enough for reading documents on screen. 300 DPI is better for printing or OCR.
Is it safe to compress a PDF with my ID?
This tool works in your browser, so the file stays on your device.
How do I compress a PDF to 100 KB?
Set 100 as the target in KB. For multi-page scans this may need low quality, so check legibility.
Does compressing a PDF reduce quality?
Images lose some detail. Text rendered as images may also look softer.