Nothing is uploaded. When you drop or pick a PDF, the tool reads it locally with the browser’s File API, renders its pages in memory with the pdf.js engine (whose worker is bundled locally, not fetched from a CDN) and rebuilds the compressed file with the pdf-lib library on your own machine. There is no server, upload, database, API or tracking in the processing path, so contracts, résumés, invoices, scans and private paperwork you are shrinking for an email or a portal stay on your device; the tool works offline once cached, and closing the tab discards everything. The only optional network use anywhere on the site is consent-gated advertising, which never sees your files.

At 5 MB the tool rarely has to work hard. Reaching any target uses lossy compression — images are down-sampled to a lower DPI and re-encoded as JPEG — but because 5 MB is one of the roomiest targets here, the downward sweep of quality often stops very early or is not needed at all, so a report, bundled scan set or slide deck lands under 5 MB looking almost untouched and typically keeps its text live and searchable (vector text and fonts are never rasterised unless a page has to be rebuilt as an image). Three variants are generated in one pass (Best Quality, Balanced and Smallest) and the tool defaults to the best one that still fits. Only a very large, image-heavy file — many tens of megabytes of high-resolution scans — is compressed firmly enough that fine detail softens; even then the result stays legible, and if you need maximum fidelity you can pick the Best Quality variant.

A 5 MB per-file ceiling is one of the most widespread on the web. It is a safe email margin: it fits comfortably inside Gmail’s 25 MB and Outlook’s 20 MB limits even after the roughly 33% Base64 encoding overhead that email adds on the wire, and it clears the tighter 10 MB caps many corporate Exchange servers enforce. It is also the stated per-file limit on many job-application and résumé portals — Indeed, Greenhouse, Workday and similar systems — and turns up on insurance-claim and invoice uploads and on a range of government and council e-service forms. This tool targets that exact number: drop your PDF and download a version that clears 5 MB, then attach it with confidence. If a portal specifies a tighter limit, a 4 MB, 2 MB, 1 MB or smaller KB preset is one click away, and a looser 10 MB cap has its own preset.

The tool is 100% client-side, so it works in any modern browser on Android, iPhone, iPad, Windows, macOS or Linux without installing anything. Because the compression happens on your own device with pdf.js and pdf-lib, it keeps working offline once the page has loaded once — useful when you are finishing an application or sending an email on patchy Wi-Fi. One PDF is processed at a time and the practical size ceiling is your device’s memory, so a very large scan is bounded by available RAM; on a phone, extremely heavy files may compress more slowly, but for the ordinary documents that need to fit a 5 MB box it is quick and stays entirely on the device.