150KB is roughly one-seventh of a typical 1MB scanned page. If you're trying to fit a multi-page scan into that space, the math simply doesn't work — there isn't enough data left to represent several high-resolution pages. That's why the smartest 150KB strategy is not about better compression, but about shrinking the amount of content first, then compressing what remains.
Strategy 1 – Pre-trim before you compress
A two-page scan of a single ID often includes a blank reverse side or a duplicate copy. Removing those pages with Remove Pages from PDF can cut the file in half before compression even begins. A one-page scan compressed to 150KB looks dramatically better than a two-page scan compressed to the same target.
Strategy 2 – Split multi-page documents
If a portal allows multiple uploads, splitting a multi-page PDF into single pages with Split PDF means each page gets its own full 150KB budget. Two uploads of 150KB each carry twice the quality of one 150KB upload of a two-page document.
How the compressor actually reaches 150KB
The tool runs a two-stage loop. Stage one is lossless: re-saving with object streams and stripping unused resources, which almost always meets 150KB for text-only PDFs. Stage two kicks in only if needed — it renders each page as an image at a candidate resolution and JPEG quality, measures the resulting file size, and walks down a grid of (scale × quality) pairs from highest to lowest until the output fits under 150KB. The loop stops as soon as it succeeds, so you always get the highest possible quality that still fits.
Why text survives better than images
In the lossy stage, the entire page becomes an image — but the top of the grid uses fairly high resolution (1.5× scale at 0.92 quality). At that level, black text on white paper renders cleanly enough to be indistinguishable from the original at normal reading size. Problems only appear when the file is too complex to fit 150KB at that quality level, forcing the tool to drop to 0.7× or 0.5× scale where text edges start to soften.
Practical rules of thumb
- One page per PDF is the ideal shape for 150KB compression.
- Photo-and-signature PDFs work beautifully — they're the tool's best case.
- Text-only PDFs never lose quality at 150KB; lossless handles them entirely.
- Multi-page scans are the hardest case. Trim first, split if possible, and expect softer images.
- Keep the original somewhere safe so you can regenerate at a different target later.
Privacy: even more important at 150KB
Documents compressed to 150KB are almost always highly sensitive — Aadhaar, PAN, marksheets, signatures, passport photos. There is no reason to hand them to a random server. This tool never uploads your file. Everything runs in your browser tab, and you can even disconnect from the internet after the page has loaded and compression will still work.