How to Compress a PDF on Mac and Windows
On a Mac, the built-in Preview app shrinks a PDF for free. Windows has no one-click compressor, so you use a free offline app. Both keep the file on your device — nothing is uploaded.
The short answer
- ✓ Mac: open the PDF in Preview, choose File → Export, open the Quartz Filter pop-up, choose Reduce File Size, and save with a new name so you keep the original.
- ✓ Windows: there is no built-in one-click compressor. Re-printing to Microsoft Print to PDF or re-exporting from Word helps sometimes; for reliable results use a free offline app (covered below). Zipping the file does not actually compress a PDF.
- ✓ The trade-off: built-in tools are free and stay local but give you little control. To choose the quality, hit a target size, or compress many files at once, use a desktop app.
How to compress a PDF on Mac (Preview, step by step)
macOS includes everything you need — no download required. Preview can shrink a PDF in a few clicks.
Open the PDF in Preview (double-click it, or right-click → Open With → Preview).
Choose File → Export from the menu bar.
In the Export dialog, open the Quartz Filter pop-up menu.
Choose Reduce File Size.
Click Save, and give the file a new name so your original stays intact.
These are Apple's official steps — see Apple Support: Reduce the size of a PDF in Preview for the canonical reference.
The catch with Preview's Reduce File Size
Reduce File Size is a single, fixed Quartz filter tuned for maximum reduction. It down-samples images hard and gives you no slider to dial it back, so on image-heavy PDFs the result often looks soft — the most common complaint online is that the compressed file is "hardly readable." You can install a custom Quartz filter, or use Automator or the Terminal, to control the amount, but those routes are fiddly. If you want to choose the quality or aim at a specific size, a desktop app is simpler.
How to compress a PDF on Windows (the honest options)
Here is the truth most pages skip: Windows has no built-in one-click PDF compressor. These are your realistic free options, in order of how well they actually work.
Re-print to Microsoft Print to PDF
Open the PDF, press Ctrl+P, choose Microsoft Print to PDF as the printer, and save. This sometimes shrinks a bloated PDF, often does little, and can rasterize or flatten the page — losing selectable text. Worth a quick try, not reliable.
Re-export from Word or Office
If the PDF came from a Word document you still have, reopen the source, choose Save As or Export to PDF, and pick "Minimum size (publishing online)." This only works when you have the original file, not the PDF alone.
The zip "trick" — don't bother
Right-click → Send to → Compressed (zipped) folder is widely suggested, but a PDF is already a compressed format, so zipping it barely changes the size — and the recipient still has to unzip it. This is not PDF compression. Skip it.
Use a free desktop app (reliable)
The dependable option is an app that compresses the PDF itself — its embedded images and structure — instead of relying on a print or zip workaround. It keeps the file on your computer and gives you control over how much it shrinks. See the steps below.
The two problems built-in tools leave you with
On Mac: no quality control
Preview's Reduce File Size is one aggressive setting. There is no "a little" or "a lot" — you get whatever the filter produces, and on photo-heavy PDFs that often means visibly degraded images you cannot undo without starting over.
On Windows: no native tool at all
With nothing built in, the common advice is "use an online compressor" — which means uploading your PDF to a stranger's server. Neither the Mac nor the Windows built-in path lets you hit a specific size (250 KB, 1 MB) or compress a whole folder of files at once.
Compress a PDF offline on both Mac and Windows (with control)
A desktop app like FileHop works the same way on macOS and Windows, so you learn one set of steps instead of relying on Preview on one machine and a workaround on the other. The PDF never leaves your device.
Open FileHop and add your PDF
Launch the app and select the PDF you want to shrink. No account, no internet connection needed.
Choose Compress
Pick the Compress PDF tool from the list.
Pick a quality level
Choose a clear trade-off between a smaller file and higher quality — maximum compression for the smallest size, balanced for everyday use, or preserve quality when the document needs to stay sharp.
Optionally strip metadata
Turn on Remove metadata if you want to strip author names and edit history. This is off by default, so enable it deliberately when privacy matters.
Compress and save
Click Compress and save the result. No upload, no account, no file-size cap — it works fully offline, identically on Mac and Windows.
Compress a PDF to a specific size (250 KB, 1 MB, 2 MB, 5 MB)
The built-in Mac and Windows methods give you no size target — you just get whatever the filter produces and have to guess. To clear a portal's upload limit, use a flow that aims at a size. FileHop has dedicated options to compress a PDF to a target locally, so you can hit the cap without trial and error and without uploading the file.
Built-in vs offline app vs online tool
Each approach has an honest trade-off. Here is how they stack up so you can pick the right one.
| What matters | Built-in (Mac Preview) | Online tool | FileHop (desktop app) |
|---|---|---|---|
| Needs install? | No | No | Yes |
| Works offline? | Yes | No | Yes |
| File leaves your device? | No (local) | Yes (uploaded) | No (local) |
| Quality control? | None | Some | Yes |
| Target size? | No | Some | Yes |
| Batch / many files? | One at a time | Usually limited | Yes |
| Cost? | Free | Free with limits | Free |
| Platforms | Mac only | Any browser | Mac & Windows |
The honest summary: built-in tools and online tools need no install — that is their advantage. FileHop's only trade-off is that you install it. In return you get quality control, target sizes, batch compression, and the file never leaving your device, the same way on both platforms.
Keep sensitive PDFs off online compressors
Both Mac Preview and a desktop app keep the file on your computer. The risk appears the moment Windows users — who have no native tool — are pushed to an online compressor, because the PDF is then uploaded to a third-party server. For IDs, contracts, and medical or financial documents, compress locally instead.
Why you shouldn't upload sensitive files to online converters →Why did my PDF get bigger or not shrink?
A few common reasons, and what to do about each.
It's already mostly text
Text is stored efficiently, so a text-heavy PDF is already small and has little to remove. A re-save can even add a little overhead, making the file slightly larger.
It's a scanned, image-heavy PDF
Scans are essentially images, so the savings come from compressing those images. Preview's filter or a print workaround may not do this well — you need image-level compression from a dedicated tool.
Preview's filter increased the size
On text-light files the Reduce File Size filter can occasionally make the PDF larger. Use a compressor that actually targets embedded images and removes duplicate objects and metadata.
Frequently Asked Questions
Can I compress a PDF on my Mac without any extra software?
Yes. The built-in Preview app does it for free. Open the PDF in Preview, choose File > Export, open the Quartz Filter pop-up menu, choose Reduce File Size, and Save with a new name so you keep the original. The catch is that Reduce File Size is a single, fairly aggressive setting with no quality slider, so the result can look soft. If you need to control how much it compresses or hit a specific size, a desktop app gives you that choice.
How do I reduce a PDF's size on Windows?
Windows has no built-in one-click PDF compressor. Your free options are: re-print the PDF to 'Microsoft Print to PDF' (helps sometimes, not always); if the PDF came from Word, re-export it with the 'Minimum size' option; or use a free desktop app that compresses the PDF itself. Zipping the file (right-click > Send to > Compressed folder) does not meaningfully shrink an already-compressed PDF, so it is not real compression. A desktop app is the reliable, controllable option and keeps the file on your computer.
Why does the Mac 'Reduce File Size' option make my PDF look blurry?
Preview's 'Reduce File Size' is a single fixed Quartz filter tuned for maximum reduction, so it down-samples images hard and gives you no way to dial it back. On image-heavy PDFs the result can look soft or unreadable. To control the trade-off, use a tool with selectable quality levels so you can choose a gentler compression that keeps text and images sharp.
Does the Mac Preview compression upload my PDF anywhere?
No. Preview compresses the PDF entirely on your Mac — nothing is uploaded. The privacy risk only appears when Windows users, who have no built-in tool, are sent to an online compressor that requires uploading the file to a third-party server. For sensitive PDFs, compress locally on either platform instead of uploading.
How do I compress a PDF to a specific size like 250 KB or 1 MB?
The built-in Mac and Windows methods give you no size target — you just get whatever the filter produces. To hit a specific size for an upload limit, use a tool that lets you aim at a target. FileHop has dedicated flows to compress a PDF to 1 MB, 2 MB, or 5 MB locally, so you can clear a portal's cap without trial and error and without uploading the file.
Is there a free way to compress a PDF on both Mac and Windows the same way?
Yes. A free desktop app like FileHop works identically on Mac and Windows: add the PDF, choose Compress, pick a quality level, optionally strip metadata, and save. Using one app on both platforms means the same steps and the same control everywhere, instead of relying on Preview on Mac and a workaround on Windows.
Can I compress several PDFs at once?
Not with the built-in tools — Preview and the Windows print/export methods handle one file at a time. A desktop app can batch-compress a whole folder of PDFs in one pass, which is the practical way to shrink many documents before sending or archiving them.
Does compressing a PDF lose quality?
It can, depending on how hard you compress. Compression mostly shrinks the embedded images; text usually stays sharp. Light compression is close to lossless; aggressive settings (like the Mac built-in filter) can soften images noticeably. Using a tool with selectable quality lets you pick a level that balances size against how the document looks — see our guide on reducing PDF size without losing quality for the detail.
Why did my PDF get bigger or not shrink at all when I compressed it?
If a PDF is mostly text it is already small, so there is little to remove and the file may not shrink — and a re-save can occasionally add a little overhead. Real savings come from compressing embedded images or removing metadata and duplicate objects, which a dedicated compressor does and the basic built-in filters may not. If a scanned, image-heavy PDF won't shrink, you need image-level compression.
Do I need an internet connection to compress a PDF?
Not if you use a built-in or desktop method. Preview on Mac and a desktop app like FileHop both work fully offline — the PDF never leaves your device. Only online compressors require internet, because they upload your file to their servers. Offline is faster for large files and keeps private documents private.
Compress PDFs the same way on Mac and Windows
FileHop compresses PDFs locally on your computer — choose the quality, hit a target size, do many at once. Free, offline, no upload.
Download FileHop Free - Mac & Windows