Reduce PDF size in KB
Type the size your form asks for. We find the best quality under it.
100% Browser-Based — Files Never Leave Your Device
About Reduce PDF Size in KB
Enter any limit, like 150 KB for a job portal or 1 MB for email, and the tool searches image quality (and, only if needed, image resolution) until the PDF is strictly under it, keeping as much quality as the limit allows. Text and vector graphics are never rasterised, so they stay sharp and selectable. For scanned documents, the Grayscale and Black & white modes reach far smaller sizes while keeping text crisp. Everything runs in a background Web Worker in your browser.
How to reduce PDF Size in KB
- Select the PDF you need to shrink.
- Enter the maximum size in KB or MB, or tap a preset. For scans, pick Grayscale or Black & white.
- Click “Reduce PDF size” and download the result.
Frequently asked questions
Is it safe to reduce my PDF here? Are my files uploaded?
Nothing is uploaded. PDFToolsFast runs entirely in your browser using JavaScript and Web Workers, so your files stay on your device. You can even disconnect from the internet after the page loads and the tool keeps working.
What sizes can I enter?
Any size from 10 KB upwards, in KB or MB. Presets cover the most common upload limits: 20, 50, 100, 200 and 500 KB.
Will the result be exactly the size I enter?
Just under it, at the highest quality that fits. We aim below N × 1000 bytes, so it passes portals that count a KB as either 1000 or 1024 bytes.
What if my PDF can’t get small enough?
You’ll see the smallest size reached. For scans, switch to “Grayscale scan” or “Black & white scan”: a black & white page is often 5–10× smaller with sharper text. Removing unneeded pages with Split PDF also helps.
Will the text become blurry?
No. Only embedded photos and scanned images are re-encoded. Digital text and vector graphics are left untouched, so they stay sharp and selectable.
Is it really free? Are there limits or watermarks?
Yes, it is free with no sign-up, no daily task limit and no watermark. Because your own device does the work, we have no per-file server costs to pass on.