Compress PDF to 400 KB

Reduce your PDF to under 400 KB for online forms, exam applications and email, without uploading it anywhere.

100% Client-Side Privacy — Your files never leave your device

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Supported: .pdf•Max 50MB•100% In-Browser

Compress to a specific size: 20 KB · 50 KB · 100 KB · 150 KB · 200 KB · 300 KB · 400 KB · 500 KB · 1 MB · 2 MB

Reduce PDF size to 400 KB for online forms

Limits around 400 KB come up on some state government, university and recruitment portals for multi-page certificates and supporting documents. Always check the exact limit in the official notification or on the portal, because limits differ between forms.

How to compress a PDF to 400 KB

  1. Click Select PDF file above and choose your document (on a phone, pick it from Files or Downloads).
  2. Check that Fit to a size is selected and the limit shows 400 KB.
  3. Click Compress PDF and wait a few seconds.
  4. Download the smaller PDF and upload it to the form.

Other sizes

Compress PDF to 20 KB · Compress PDF to 50 KB · Compress PDF to 100 KB · Compress PDF to 150 KB · Compress PDF to 200 KB · Compress PDF to 300 KB · Compress PDF to 500 KB · Compress PDF to 1 MB · Compress PDF to 2 MB · Guide: reduce PDF size for government forms

Frequently asked questions

How do I compress a PDF to 400 KB?

Upload your PDF on this page. The size is already set to 400 KB, so just click "Compress PDF". PDFAdore tries gentle settings first and only compresses harder if needed, then you download the result.

Will my PDF still be readable at 400 KB?

For most documents, yes. Text and images are kept as sharp as the 400 KB limit allows. For very long or image-heavy PDFs, pages may be saved as images to fit, so the text is no longer selectable but stays readable.

What if my PDF cannot get under 400 KB?

Very long documents sometimes cannot fit a small limit. Split the PDF into parts with Split PDF, remove pages you do not need, or upload each page separately if the form allows it.

Is my document uploaded to your servers?

No. Compression runs entirely in your browser, on your own phone or computer. Your PDF is never uploaded.