PDFs
How to Reduce PDF File Size on Mac (Without Uploading It Anywhere)
A PDF exported from InDesign, Acrobat, or Keynote routinely lands at 30–80 MB — well past most email attachment limits, and painful to share over a slow connection. Here is how to reduce a PDF's file size on Mac using Smol, entirely offline, in whatever quality tier actually matches what the file is for.
Step by step
Drop your PDF into Smol
Drag one PDF or a folder of them onto the Smol window. Nothing uploads — the file stays on your Mac through the entire process.
Pick a quality preset
Choose from five presets: Tiny (72 DPI, smallest possible, email-ready), Small (150 DPI, good for sharing), Medium (300 DPI, everyday use), Large (300 DPI, print-quality), or Original (no downsampling, metadata cleanup only).
Compress
Smol re-encodes the images inside the PDF at the target resolution and quality while leaving text and vector content sharp — text in a PDF is not raster data, so it never loses quality regardless of the preset chosen.
Check the result
Smol shows the exact size reduction achieved. A 50 MB InDesign export with several high-resolution images typically lands at 3–5 MB on the Small preset — small enough for any email provider — while staying legible on screen.
Why PDFs get so large in the first place
Design and publishing tools embed images inside a PDF at whatever resolution they were placed at — often 300 DPI or higher, sized for print, even when the PDF will only ever be viewed on a screen. A handful of print-resolution photos is usually the entire reason a document balloons to tens of megabytes; the text and layout data contribute almost nothing to the total size by comparison.
Which preset to use for what
Tiny and Small are built for email and quick sharing — 72–150 DPI is more than enough resolution for a document read on a screen. Medium is a safe everyday default that keeps images looking sharp on a high-resolution display without carrying print-grade weight. Large and Original exist for when the PDF is actually headed to a printer, where downsampling below 300 DPI would show.
Why offline compression matters for PDFs specifically
PDFs disproportionately carry sensitive content — contracts, NDAs, financial statements, unreleased creative work — which makes uploading them to a browser-based compressor a real exposure, not just an inconvenience. Smol never uploads a file anywhere; every byte of processing happens on your Mac's own CPU, which also means there is no daily cap the way free web tools like Smallpdf (2 PDFs/day) or Adobe's own compressor typically impose.
Frequently asked questions
How do I compress a PDF on Mac without losing text quality?
Text and vector content in a PDF are not raster images, so compression presets that target image resolution never touch text sharpness — it stays crisp at every quality level. Only embedded photos and scanned pages are affected by the DPI setting you choose.
What is the best PDF compression setting for email?
Small (150 DPI) is usually the right balance — small enough to clear most email attachment limits while still being comfortable to read on screen. Tiny (72 DPI) goes further if the file is still too large.
Can I compress a PDF without uploading it online?
Yes — that is the specific gap Smol fills. All compression happens locally on your Mac; the file is never transmitted anywhere, which matters for contracts, medical records, or any document under an NDA.
How much smaller can a PDF get?
A 50 MB InDesign export with several print-resolution photos typically compresses to 3–5 MB on the Small preset — a 70–90% reduction is common for image-heavy PDFs. Text-only PDFs have much less to gain, since there is little image data to compress.
Can I batch-compress multiple PDFs at once on Mac?
Yes. Drop a folder of PDFs into Smol and it processes all of them in one pass, applying the same preset to each and showing individual results per file.
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