How to Compress a PDF to Under 100KB
Use the Low quality setting to get PDFs as close to 100KB as possible. Exact byte-for-byte sizing isn't possible with any browser-based compressor, but Low quality typically gets image-heavy PDFs into this range.
Compress your PDF (Low quality is pre-selected)
Drop a PDF here
or
What to expect at this size
Hitting ~100KB depends almost entirely on what's in your PDF. A 2 MB scanned single-page invoice will usually land between 60KB and 140KB on Low. A 10-page full-colour brochure will land between 300KB and 800KB no matter how hard you compress — there's a real floor set by page count and image content.
On the Low preset, embedded raster images are downscaled to roughly 1200 px on the long edge and re-encoded as JPEG at quality 55. That's enough to keep printed text legible at A4 / Letter sizes while removing most of the file weight. Vector text and line art are left alone, but on Low the page may be rasterised — meaning text becomes part of the page image, not a selectable text layer.
If your file lands above 100KB and you need it smaller for an upload form: delete unnecessary pages in any free PDF reader before compressing, or split the document. Pushing compression harder usually just makes the result unreadable rather than smaller.
Quick checklist
- Start with Low quality (already selected above).
- Single-page or 2–3 page documents will land closest to 100KB.
- Image-heavy scans compress far more than vector text documents.
- If you must hit a hard cap, reduce page count before compressing harder.
Common questions
- Will this hit exactly 100KB?
- No — and no browser-based PDF compressor can reliably do that. Output size depends on your document's page count, image content, and resolution. We aim close to 100KB on Low quality and show you the actual result; you decide if it's small enough.
- Why can't you just iterate until the file is exactly 100KB?
- We could, but the result would look terrible below the natural floor of your document. Iterative re-compression past the JPEG quality-30 threshold produces visible blocking and unreadable text, which isn't a tradeoff most users actually want.
- Will the compressed PDF still have selectable text?
- On Low quality, often no. The page is rasterised, so text becomes an image. If you need selectable text, use Medium or High on the main Compress tool and accept a larger file.
- Is my PDF uploaded to a server?
- No. Everything runs in your browser via WebAssembly. The file never leaves your device, even on this landing page.