Compress to 150 KB

Compress a PDF to 150 KB

Q: How do I compress a PDF to 150 KB?

Open Compress PDF, type 150 KB as the target and add the file. It is recompressed just enough to fit, and the final size is shown to the byte. Nothing is uploaded.

150 KB is the edge. A typed document or a one- or two-page scan gets under it with the text still selectable; a longer scan usually only fits once its pages are flattened into pictures. Type 150 KB, run it, and read the result line: it says whether flattening was needed.

By Suprabhat Updated October 23, 2026 How we write these

Open Compress PDF with 150 KB filled in Free · no upload · no watermark · runs on pdf-lib, pdf.js, MozJPEG in your browser

Who asks for 150 KB?

Exam and recruitment portals that set one limit for every certificate you upload.
University applications asking for a single transcript or mark sheet page.
Visa and travel forms that cap each supporting document separately.
Bank and KYC uploads of an address proof or a utility bill.

What to expect at 150 KB

A typed letter or form: Easy. Text costs almost nothing; most are already well under.
A one- or two-page scan: Comfortable, with the text layer kept and print still clear.
A three- to five-page scan: On the line. Often reachable by recompressing alone if the scan is grayscale; a color scan may need flattening.
A long scan or a photo-heavy file: Only flattened, at low resolution. Split it, or send fewer pages if the form allows.

How to do it

1 If you are scanning now, scan in grayscale A color page carries three channels of picture for what is usually black print on white paper. Grayscale at 200 dpi gives the compressor far less to squeeze, which is often what keeps a scan out of flattening at this size.
2 Open Compress PDF with 150 KB filled in The button at the top of this page sets Make the PDF smaller than to 147 KB, a little under the limit. The file is read in your browser and never sent anywhere.
3 Choose what matters if it doesn’t fit Under Advanced, Flatten pages if that’s the only way to hit the target is what lets a long scan reach 150 KB. Leave it on if the form only needs to see the page; turn it off if the text must stay selectable, and the tool tells you instead of flattening.
4 Read the result line It gives the exact size and says whether pages were flattened. Flattened pages look the same but no longer have text you can select or search.
5 Still over? Cut pages, not quality Remove blank backs and duplicate pages with Delete PDF Pages, or split the file if the portal accepts more than one. Each page you drop is budget the others keep.

Why 150 KB is where scans start to lose their text

A scanned page is a photograph, and photographs can only shrink so far before the compressor has to redraw them. Recompressing keeps the page as it is — including any text layer a scanner added — and only lowers the picture quality. Flattening re-photographs the whole page at a lower resolution, and the text layer does not survive.

Around 150 KB, the first method runs out for anything beyond a few pages. That is why the same five-page scan that reaches 200 KB intact may only reach 150 KB flattened, and why the result line tells you which happened.

If the document will be read back by a person, a flattened page is fine. If it will be searched, copied from or converted later, keep a larger copy too.

A form that says 150 KB usually checks the exact byte count. Aim for 140 KB rather than 149.

Questions

How do I compress a PDF to 150 KB?

Open Compress PDF, type 150 KB as the target and add the file. It is recompressed just enough to fit, and the final size is shown to the byte. Nothing is uploaded.

Why did my scan only reach 150 KB after flattening?

Because recompressing the pictures wasn’t enough on its own — common for scans of more than a few pages, and for color scans. Scanning in grayscale, or removing pages you don’t need, often lets it fit without flattening.

Is 150 KB the same as 0.15 MB?

Usually: 150 KB is 150,000 bytes, which is 0.15 MB. Some portals count a kilobyte as 1,024 bytes instead, which makes the limit a little larger — so a file just under 150,000 bytes passes either way.

Can I compress a PDF to 150 KB on my phone?

Yes. Compress PDF runs in the phone’s browser — Safari or Chrome — with nothing to install, and the file stays on the phone.