A Mac is better at PDFs than most people realise — Preview alone can merge, sign, and reorder pages. But it has real blind spots: its one-click “Reduce File Size” often turns a crisp document into a blurry one, and it can’t convert a PDF to Word or run OCR at all. This guide covers what Preview does well, where it falls short, and how to fill the gaps in your browser without installing anything.
What Preview already does — and does well
Before opening anything else, Preview (built into every Mac) handles a surprising amount:
- Merge and reorder — open a PDF, show the sidebar (thumbnails), and drag pages around or drag a second PDF in.
- Sign — use the Markup toolbar’s signature tool (create one with your trackpad or camera).
- Rotate and delete pages, and rearrange with a drag.
- Save anything as PDF — in any app, choose File → Print → the PDF dropdown → Save as PDF.
For those jobs, Preview is genuinely all you need. The trouble starts with compression, conversion, and OCR.
Where Preview falls short
Preview’s Reduce File Size (File → Export → Quartz Filter) uses one aggressive setting: it frequently makes text and images noticeably softer, with no way to dial it back. And Preview simply cannot convert a PDF to an editable Word or Excel file, or add a searchable text layer to a scan. For those, you need a proper tool.
How to compress, convert or OCR a PDF on Mac
- Open ream.pro in Safari, Chrome, or any browser and pick your tool — e.g. Compress PDF.
- Drop in your PDF and choose your setting (for compression: balanced, strong, or light).
- Download — the result appears in your Downloads folder.
Light tools like merge, organize, sign and rotate run on your Mac, in the browser, so the file never leaves your machine. Heavier tools — compress, convert, OCR — run in Ream’s isolated sandbox and are deleted immediately. More on that here.
Rule of thumb: use Preview for quick merges, signatures, and page tidying; switch to Ream the moment you need controlled compression, an editable Word file, or OCR — the things Preview can’t do.
Is it private, and is it free?
Yes. Nothing to install, no account, no watermark. Your Mac keeps the file for the browser tools, and the sandbox deletes it for the heavier ones. The exact same tools work on your iPhone or iPad, a Windows PC, or an Android phone.
Frequently asked questions
How do I compress a PDF on a Mac without losing quality? Use Compress PDF in your browser and choose the balanced or light setting — it gives you control that Preview’s single “Reduce File Size” option doesn’t.
Can I merge PDFs on a Mac for free? Yes — Preview merges via its thumbnail sidebar, or use Merge PDF in the browser for a visual drag-and-drop grid.
How do I convert a PDF to Word on a Mac? Preview can’t — use PDF to Word, which rebuilds text and tables as an editable document.
Why is my compressed PDF blurry? That’s usually Preview’s aggressive Reduce File Size. Try Compress PDF with a lighter setting for a sharper result.
How do I sign a PDF on a Mac? Use Preview’s Markup signature tool, or Sign PDF to draw or type a signature in the browser.
Do I need to install anything? No — everything runs in your browser on macOS.
Is it free? Yes — free, no sign-up, and no watermark.
Preview covers the basics on a Mac beautifully; Ream covers everything it can’t — controlled compression, conversion, and OCR — without an install. And because it’s all in the browser, the same tools travel to your iPhone, PC, and Android.
