# How to compress a PDF without uploading it (Mac, offline)

> Compress a PDF on your Mac without uploading it or being online: Preview’s free filter, and Whizra by typing “compress it”. What each one does to the file.

Source: https://whizra.com/guides/compress-pdf-without-uploading

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# Compress a PDF without uploading it

On a Mac you can compress a PDF without uploading it, and without being online. Preview does it for free with its “Reduce File Size” filter; Whizra does it when you select the PDF and type compress it.

## Free: Preview
1. Open the PDF in Preview.
2. File → Export.
3. Quartz Filter: Reduce File Size.
4. Save it under a new name, so you keep the original.

It’s free and offline, but the result is often blurry and sometimes bigger than the original ([why](https://whizra.com/guides/why-preview-makes-pdf-bigger)).

## With Whizra

Select the PDF in Finder, double-tap the right Option key and type compress it. You get “name (compressed).pdf” next to the original, and the result card shows the size before and after. Recorded on the app: the sample PDF went from 3.1 MB to 361 KB.
- Three qualities: strong, good, light. compress it for email or under 2 MB picks a strong one.
- If the result isn’t at least 5% smaller, it says so and keeps nothing.
- Text stays selectable. Scanned pages shrink less than photo-heavy brochures.
- The original is never changed. Undo moves the new file to the Trash.

## Questions

**Does it work offline?**

Yes, both. Preview and Whizra compress on your Mac. Whizra checks its license key online about once a week, but being offline never locks you out.

**Will the text in my PDF stay selectable?**

With Whizra, yes: text stays selectable.

**How small will it get?**

It depends on what’s inside: pictures shrink a lot, scans and plain text less. Whizra shows before → after on every job, and keeps nothing if it can’t save at least 5%.

Checked: 3 Nov 2026.

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Related: [Compress a PDF on Mac](https://whizra.com/compress-pdf-mac) · [Send a big PDF by email](https://whizra.com/guides/send-big-pdf-by-email)