Compress PDF to 100KB

How to Compress PDF

1

Add your PDF

Click “Select files” or drag PDFs in. The 100KB target is preselected from this page.

2

Check the target

100KB is a demanding target for scans. If your document is a scan of many pages and the limit is negotiable, 200KB roughly doubles the quality budget. Every control stays live.

3

Compress and download

Click “Compress PDF”. The engine tries its quality ladder from the top down and keeps the best version that fits; the result list shows the final size.

Every step runs in your browser. No server uploads, no waiting.

Why use this tool

This page compresses your PDF to 100KB or less, the tightest limit portals commonly impose. The limit binds the whole file, so what fits depends heavily on what the PDF is made of. A text-based document — a letter, an application, an exported form — nearly always fits with room to spare, because text compresses extremely well and is never rasterized. A scanned document is where 100KB gets demanding: the engine will lower the scan’s resolution step by step until the file fits, which keeps a short scan usable but can leave a long one either above the limit or visibly soft. The honest answer is in the result list, which shows each file’s size before and after. If the target proves out of reach, compress to 200KB instead and check whether your form truly needs 100, or convert single pages with PDF to JPG under 100KB.

When you'd use this

Exam registrations

Competitive-exam portals are the classic 100KB case: one small PDF per document, hard-rejected at the byte limit.

Low-bandwidth sharing

Documents that must travel over slow or metered connections, where every attachment kilobyte is felt.

Single-page documents

A one-page certificate or declaration compresses under 100KB almost regardless of what it contains.

Legacy system uploads

Older document-management and HR systems whose upload fields predate large storage and still enforce double-digit limits.

Why this matters for your privacy

☁️ CLOUD PDF TOOLS
📄 your-file.pdf
↓ uploaded over the internet
☁️ their server

A copy of your document sits on someone else’s infrastructure — deleted on their schedule, not yours.

✗ OUT OF YOUR HANDS
DukPdf
📄 your-file.pdf
⟳ stays right where it is
💻 your device

Processed by your own browser, start to finish — on your machine, under your control.

✓ STAYS ON YOUR DEVICE

We send the software to your file — not your file to our servers.

Compress PDF — questions

Can every PDF reach 100KB?

No, and this page will not pretend otherwise. Text documents almost always fit. Scans depend on length — a page or two usually fits, twenty pages of photographs may not. When nothing fits, you get the smallest version produced, with its size shown, rather than a fake success.

How does DukPdf get a file this small?

Three levers: images are downsampled and re-encoded at lower quality, embedded fonts are subset to just the glyphs used, and the PDF’s internal structure is rewritten compactly. Under a tight target the engine also drops optional metadata. Text content itself is never altered.

Will a scanned signature still be legible?

Usually, yes. Handwriting and stamps survive moderate downsampling because they are high-contrast. Fine print is what softens first — check the output before submitting, the way the portal’s reviewer will see it.

Is 100KB measured in 1000 or 1024 bytes?

DukPdf targets 100,000 bytes — the stricter reading. A file that passes here reads as under 100KB on both macOS (1000-based) and Windows (1024-based), so it clears the portal either way it counts.

Does this work without uploading my document?

Yes. The whole compression search runs in your browser — the file never leaves your device, which matters precisely for the ID scans and certificates these portals ask for.

Tools that pair with compress pdf

→ Merge PDFCombine multiple compressed files→ Protect PDFPassword-protect after compressing→ Edit MetadataStrip authoring metadata to shrink further→ OCR PDFMake scanned PDFs searchable first→ Split PDFExtract and compress specific pages→ Remove PagesDrop pages to reduce size further

Compress PDF for a specific size

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🔒 DukPdf — YOUR FILES NEVER LEAVE YOUR DEVICE

Ready to compress pdf? Your files stay yours.

No server uploads. No watermark. Just open a tool, drop your files, and download the result. Your original files are never modified.

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