Compress PDF to 400KB
Set a strict target size and keep the best readable result. 100% private, no upload.
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Common next steps after hitting a strict file-size limit.
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How It Works
Step 1: Check the packet composition
A five-page packet has 400 KB / 5 pages = 80 KB per page before PDF overhead. A clean cover letter uses a different amount of image detail from a photographed certificate, so count image-heavy pages as well as total pages.
Step 2: Compress from the original
The target is 400,000 bytes. ExactPDF tests JPEG quality and lower page resolutions as needed. The rebuild may remove selectable text; scanned diagrams and photographs can lose fine detail even when their page outlines look unchanged.
Step 3: Read the weakest page
Inspect the faintest scan, not just the clean cover page. If the result remains over 400 KB or important labels become unclear, choose 500 KB when allowed. If the cap is fixed, remove only pages the recipient does not require.
Why Use This Tool
- A middle step between 300 KB and 500 KB avoids jumping straight to a much larger target.
- The output is measured against the same decimal ceiling shown on the result.
- Mixed-source packets can be reviewed page by page instead of assuming the cleanest page represents the whole file.
Common Use Cases
Prepare a short onboarding packet, a cover letter with supporting documents or a compact invoice bundle for a 400 KB field. Check that a scanned attachment does not become unreadable behind an apparently clear digital first page. Retain originals for future printing and text search.
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Frequently asked questions
What does a five-page packet get from 400 KB?
400 KB / 5 pages = 80 KB per page before PDF overhead. This is a budget illustration, not a tested capacity. A packet with one dense scan may behave differently from five pages of simple text.
Why does the cover page look better than my scanned attachment?
Clean text has simpler shapes than scan noise or a photographed background. Exact-size reduction renders every page into JPEG images and can lower resolution, so faint scan details and photo textures are more vulnerable. Digital text may also stop being searchable or selectable.
Can I use a 400 KB Best Effort Result in a strict field?
Only if its actual bytes satisfy the field; an over-limit Best Effort Result has missed 400,000 bytes. ExactPDF shows the size and warning rather than claiming success. If rebuilding would grow the file, the engine keeps the original.
When should I move from 400 KB to 500 KB?
Use 500 KB when permitted and when the 400 KB result misses the cap or loses important detail. That adds 100 KB, or 25%, to the budget. For a mandatory 400 KB limit, improve the source or remove only unneeded pages.
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