MB to kB PDF Compressor

Mb2KbSizer is a free set of browser tools that shrink files to a size you choose. This page handles PDFs: you set a target in kB, MB or percent and get a document that fits it. The [home page](/) does the same for JPG, PNG and WebP photos, and the bulk image compressor processes up to 200 pictures in one go. People use it for portal uploads, lighter email attachments (Gmail, for instance, stops at 25 MB per message) and faster-loading websites.

Yes, completely. There is no premium tier, no watermark, no sign-up and no cap on how many PDFs you compress or how often. The site is paid for by the ads you see around the tool, and those ads never get access to your files.

No. Open mb2kb.online in a current version of Chrome, Edge, Firefox, Safari or Samsung Internet and the compressor is ready; there is no download, extension or plugin. If you use it often, add the page to your home screen from the browser menu and it opens like an app. It still needs an internet connection to load, because the compression code is fetched from our site each time.

Drop or browse to the PDF, type the size you need and pick kB, MB or % of original, then press Compress PDF. The tool runs on your device, shows the first page before and after with the exact byte count, and the Download button saves the result. Tick Convert to black & white for scans, or tap a quick chip such as 100 kB to jump straight to a common target. If the number is not what you hoped for, change a setting and press Compress again with these settings; nothing has to be re-uploaded, because nothing was uploaded in the first place.

This page accepts PDF files only; the file picker filters for .pdf. It does not turn Word, Excel or image files into PDFs, so export those with the app's own Save as PDF or Print to PDF option first, then compress the result here. For photos and graphics, the [image compressor](/) takes JPG, PNG, WebP, GIF, BMP and AVIF, plus HEIC in browsers that can decode it.

Nothing is uploaded, which is the whole point. The PDF is read by Mozilla's pdf.js and rebuilt by pdf-lib, both running inside your browser tab, and the finished file is assembled in your device's memory. Our web host never receives the document, only the ordinary page request, and the analytics and ad scripts on the page cannot read the file either. That makes it suitable for bank statements, medical reports and identity documents.

No. There is nowhere to put them: the tool has no database, no upload endpoint and no account system. Your original stays wherever it was on your device, the compressed copy exists only in the browser's memory until you download it, and both are released when you press Compress another PDF or close the tab. The only data we keep is anonymised usage analytics, such as how many compressions ran and which target sizes are popular, never file names or contents.

Yes, but the two behave differently. A digital PDF (exported from Word, Google Docs, a billing system or a browser) is mostly text, fonts and structure, so the lossless clean-up often does the job and the text stays selectable. A scanned PDF is really a stack of photographs, one per page, with very little to clean up, so it almost always goes through the re-render path. For scans, tick Convert to black & white and expect large savings, because a grayscale page at 150 dpi needs far fewer bytes than the colour original. If a portal demands selectable text from a scan, run it through an OCR tool before compressing; we do not add a text layer.

Not while the password is on it. The tool has to open the file to read the pages, and an encrypted PDF refuses that, so you will see a message asking you to remove the protection first. The easiest route is to open the PDF in your usual reader with the password, then use Print and choose Save as PDF (or Microsoft Print to PDF on Windows) to make an unlocked copy. Compress that copy here, and re-apply a password afterwards in your reader if the recipient needs one.

Often, but every page has to share the same budget. A 100 kB target spread across 10 pages leaves roughly 9 kB per page after a little overhead for the file structure, which is very tight: plain black-and-white text can survive, but photographs, colour logos and dense tables will look blocky. The tool hands spare bytes from simple pages to busier ones and tries up to three times, then tells you plainly if the best it could do is still above the target. When that happens, raise the target, tick black & white, or split the document so each part has a budget of its own. The result normally lands a little under the number rather than exactly on it, because the search stops at the first size that fits. Our 100 kB preset page opens with that target already filled in.

Because the re-render method was used. When the lossless clean-up cannot reach your target, every page is converted into a JPEG picture, and a picture of words is not text: screen readers, Ctrl + F and copy-paste stop working, and links and form fields disappear. The note in the result panel tells you which method ran, so you are never caught out. If selectable text matters more than the exact size, raise the target until the note says lossless optimisation was used, or trim the PDF in your editor first by removing scanned attachments, blank pages and high-resolution logos.

Yes. Open mb2kb.online in Chrome or Samsung Internet on Android, or in Safari on an iPhone or iPad, tap the drop zone and choose the PDF from Files, Downloads, Google Drive or iCloud. Processing uses your phone's own processor, so a long scanned document takes longer than on a laptop, and the page shows a progress bar while it works. The compressed file lands in your Downloads folder on Android or in the Files app on iPhone, ready to attach to a form, an email or a WhatsApp message.