Roundup
The Best PDF Compressor for Mac in 2026
Smol is the PDF compressor we would install on a Mac today: it produced the smallest file at every resolution we tested, it batches, and it costs $29 once. But macOS already ships a competent one. If you compress a PDF twice a year, use Preview and keep your money.
We make Smol, so treat the ranking as an opinion and the numbers as the argument. Every size below was measured on the same two files on the same machine, and the two tools that beat us on something real get said so in plain English: Ghostscript targets resolution more accurately than we do, and Acrobat Pro does preflight and PDF/A work that Smol cannot touch.
What we tested, and how
Measured on an Apple M2 Pro Mac with 16 GB of RAM, on 26 September 2026, using Smol 1.0.34 and Ghostscript 10.07.0. Output sizes are the exact byte counts reported by the filesystem; embedded image resolutions come from pdfimages -list (poppler) run against every output file.
The corpus is three PDFs we generated ourselves, so the files can be described precisely rather than hand-waved. They are synthetic, not client documents, and that is a real limitation: a 90-page legal bundle with scanned exhibits will behave differently from any of these.
| Test file | What it contains | Size |
|---|---|---|
| brochure.pdf | 4 US Letter pages. One 2,250 × 1,750 px photo per page placed 7.5 in wide (300 PPI), plus live vector headline and body text. | 3,734,814 bytes (3.56 MB) |
| scan.pdf | 4 pages, each a full-bleed 2,550 × 3,300 px raster of typed text with paper noise. A simulated 300 DPI scan, so there is no live text at all. | 4,062,022 bytes (3.87 MB) |
| textonly.pdf | 8 pages of vector text and rules. No raster images anywhere. The control case. | 7,095 bytes |
Comparing compressors fairly means comparing them at the same output resolution, because anything else is just measuring who resamples hardest. Preview’s built-in filter lands on 144 PPI, Ghostscript’s /ebook on 150 PPI, and Smol’s Medium preset on 160 PPI for this page geometry. Close enough to put side by side:
| Tool and setting | Image PPI out | brochure.pdf | scan.pdf |
|---|---|---|---|
| Preview, Reduce File Size | 144 | 985,682 (73.6% off) | 1,419,338 (65.1% off) |
Ghostscript -dPDFSETTINGS=/ebook | 150 | 347,619 (90.7% off) | 698,440 (82.8% off) |
| Smol, Medium | 160 | 288,810 (92.3% off) | 281,498 (93.1% off) |
Preview is carrying roughly three times the bytes of the other two at a slightly lower resolution, which tells you the gap is encoder efficiency, not aggression. Ghostscript and Smol are within a rounding error of each other on the brochure and a factor of 2.5 apart on the scan.
Four of the seven tools below we could not run: Acrobat Pro, Smallpdf, iLovePDF and PDF Squeezer are all paid or account-gated, and we are not going to upload a test corpus to three different servers to produce numbers we cannot reproduce. Those four are assessed on published capability and price, and the writeups say so.
If you need X, pick Y
| If you need | Use |
|---|---|
| One PDF under an email limit, right now, nothing installed | Preview |
| A folder of 25 PDFs, repeatedly, with quality you choose | Smol |
| An exact DPI target enforced regardless of page size | Ghostscript |
| PDF/A archival output, preflight, or true redaction | Acrobat Pro |
| Separate settings for colour, greyscale and monochrome images | Acrobat Pro |
| To compress on a Windows PC or a borrowed machine | iLovePDF |
| A document that must never leave your Mac | Smol, Preview or Ghostscript |
| A cheap single-purpose app from the Mac App Store | PDF Squeezer 4 |
Smol
Five presets, local processing, and images, video and audio in the same window.
Smol produced the smallest output at every resolution we tested, and the margin over Preview is not subtle. Drop brochure.pdf in at Small and it comes out at 153,911 bytes, 95.9% off. At Medium, which keeps 160 PPI images, it lands at 288,810 bytes against Preview’s 985,682 at a lower 144 PPI. The reason is unglamorous: the images are re-encoded with mozjpeg rather than the system JPEG encoder, and the file is finalised with qpdf --linearize --object-streams=generate, which collapses the document’s structural objects into compressed streams.
There are five presets. Tiny, Small, Medium, Large and Original cap the longest pixel edge of every embedded image at 600, 900, 1200, 1800 and 2400 px and re-encode at JPEG quality 25, 45, 60, 75 and 88. We explain what that means for real page sizes in what PDF compression presets actually do, including why Original still cut our 3.56 MB brochure to 1,818,893 bytes.
Batch is where the price justifies itself. We duplicated the brochure 25 times, 89 MB on disk, dropped the folder in at Small, and the job reported 4,230 ms wall clock for all 25 files. That is about 0.17 s per document, against 0.39 s for a single file through Ghostscript on the same Mac. There is no per-file limit, no queue and no upload, and the same window also takes images, video and audio, which is the actual reason most people stop keeping four tools around.
Honest limits: macOS only. It does not do preflight, PDF/A, redaction, OCR or page editing, and it will not re-subset fonts. It also does not strip PDF document metadata as part of compression. We checked, and the Producer, Creator, Title and CreateDate fields survive every preset, so if you need those gone that is a separate step.
Smol is $29 once for one Mac, $49 for a three-licence team pack, with updates included. No subscription and no account.
macOS Preview
Already on your Mac, genuinely adequate, and free.
Open the PDF, File → Export, set Quartz Filter to Reduce File Size, save. On our brochure that produced 985,682 bytes from 3,734,814, a 73.6% reduction, in about 0.19 s. For a single contract you need to email in the next two minutes, that is the correct answer and everything below it is overkill.
The old complaint that Preview destroys PDFs deserves a correction. You can read the filter yourself: plutil -p "/System/Library/Filters/Reduce File Size.qfilter". When we read it on 26 September 2026 it resampled images to 144 PPI with a 2,400 px ceiling and re-encoded them as JPEG at quality 0.7, with interpolation on. That is a reasonable screen-reading target, not the destruction the internet still describes. Our output measured exactly 144 PPI on both test files.
What Preview does not give you is a dial. It is one filter with fixed values, plus three yes/no checkboxes Apple documents in the Preview user guide: Create Linearized PDF, Optimize images for screen, and Save images as JPEG. If 144 PPI at quality 0.7 is not small enough, Preview has no next move, and the file is still three times the size of what mozjpeg produces at the same resolution.
Batch is possible and almost nobody knows it. macOS ships Automator actions called Apply Quartz Filter to PDF Documents and Compress Images in PDF Documents; wire either into a Folder Action or a Quick Action and you have free batch compression. It is fiddly to build and it overwrites in place unless you are careful, which is why most people do it once and never again.
Adobe Acrobat Pro
The only tool here that does preflight, PDF/A and real redaction.
Acrobat is not a PDF compressor, it is a PDF production suite that happens to contain the most granular compressor on this list. File → Save as Other → Optimized PDF opens the PDF Optimizer, whose Images panel sets compression and downsampling separately for colour, greyscale and monochrome images. Nothing else here distinguishes a scanned signature block from a product photo, and for mixed documents that distinction is the whole game.
Preflight is the other genuine differentiator. Acrobat Pro ships fixups under Tools → Print Production → Preflight, including a profile that downsamples colour and greyscale images to 150 ppi and bitmaps to 300 dpi, plus colour-space conversion and PDF/A output for archival requirements. If a client, a court or a printer has specified PDF/A-2b, Smol cannot help you and Acrobat can. We say that without qualification.
The cost is the problem. Adobe’s own pricing page lists Acrobat Pro for individuals at US$239.88 per year prepaid, US$19.99 per month on an annual commitment, or US$29.99 per month with no commitment. Perpetual licences ended after Acrobat 2020; Adobe now offers a one-time Acrobat Pro 2024 purchase that grants three years of desktop access with quarterly security updates but no feature updates and no online services.
Buying a $239.88-a-year subscription to make PDFs smaller is a bad trade. Buying it because you need preflight, redaction, forms and PDF/A, and getting a good compressor in the box, is a perfectly sensible one. Which of those you are doing is a question only you can answer, and a lot of people answer it wrong.
Ghostscript
The reference implementation. Targets true DPI, and beats us at it.
One command, no interface: gs -sDEVICE=pdfwrite -dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH -sOutputFile=out.pdf in.pdf. On Ghostscript 10.07.0 that took our brochure from 3,734,814 to 347,619 bytes in 0.39 s. /screen went further, to 125,624 bytes.
Here is where Ghostscript beats Smol, and it is a real architectural win rather than a rounding error. Ghostscript resamples to a genuine resolution target because it knows how large each image is placed on the page. /screen produced exactly 72 PPI on both test files despite their different page geometry; /ebook produced exactly 150 PPI on both. Smol caps pixel dimensions instead, so its Tiny preset gave 80 PPI on the brochure and 55 PPI on the full- bleed scan. If you need “nothing above 150 DPI, ever, regardless of page size”, Ghostscript enforces that and we do not.
Two warnings. First, /printer and /prepress did not shrink our files at all: they came out 0.3% and 0.1% larger than the input, because both presets leave 300 PPI images alone and the rewrite costs a few kilobytes. People reach for /prepress expecting high-quality compression and get a slightly bigger file. Second, Ghostscript rebuilds the document rather than editing it, which is thorough but means annotations, form fields and tagging can change.
The licence matters if you are shipping something. Artifex dual-licenses Ghostscript under the GNU AGPLv3, and their licensing page is explicit: if you cannot meet the AGPL requirements, including disclosing your application’s source when deployed as a server-based service, a commercial licence is required. Fine for your own Mac, a real decision for a product. Full walkthrough in how to compress a PDF on Mac.
PDF Squeezer 4
A small, focused, actively maintained Mac App Store app.
Daniel Witt’s PDF Squeezer has been the default indie answer to this problem for years, and the App Store listing we checked on 26 September 2026 showed version 4.9 with an update dated within a day, requiring macOS 13.0 or later. Anyone telling you it is abandoned has not looked recently. It is $19.99 on the Mac App Store; the developer’s own site was running a 50% promotion to $9.99 the same day.
It does one job: drop PDFs, pick a compression profile, get smaller PDFs. It supports batches, custom profiles with your own DPI and quality values, and automatic folder processing. For a reader who wants a cheap App Store app that compresses PDFs and nothing else, this is a completely reasonable purchase and we would not argue with it.
We did not benchmark it: we do not own a licence and will not publish numbers from a trial build we cannot re-run. What we can say is scope. PDF Squeezer is a PDF tool, so it will not touch the 4K screen recording, the folder of HEICs or the podcast WAV sitting next to your PDFs. That is the argument for paying a little more for something broader, and if PDFs really are all you have, it does not apply to you. The App Store listing shows no rating, so there is no crowd signal either way.
iLovePDF
The best free web tool, with limits that are honest about themselves.
iLovePDF is the web compressor we would send a non-technical friend to, and it wins on reach: it works on a Windows machine, a Chromebook, a locked-down work laptop, or a phone. No Mac app on this list does any of that. Three quality levels, a clean interface, and the free tier is usable rather than a bait tier.
The limits are worth stating precisely, because they are usually reported wrong. Reading the pricing page directly on 26 September 2026: the free Compress PDF tool handles 2 files per task with a 200 MB per-task size cap. Premium raises that to 10 files per task and 4 GB. So “two compressions” is a misreading; two files at a time is the real constraint, and for a single document the free tier is genuinely fine.
Premium is listed at US$4 per month billed annually, shown as US$48 per year, or US$7 billed monthly. That is the cheapest subscription here by a distance, and if you want a browser tool rather than an app it is decent value.
The cost is the one you already know: the file goes to someone else’s server. For a conference flyer nobody cares. For a signed NDA, a medical record or a client’s unreleased artwork, uploading is a decision with consequences, and it is the whole reason local apps exist. Every upload is also bounded by your upstream bandwidth, which on most home connections is the slowest part of the operation.
Smallpdf
The polished browser suite, at the steepest subscription on this page.
Smallpdf is the most designed product in this roundup. Compression is one tile in a suite covering merging, splitting, converting, e-signing and OCR, and if your team already works that way, adding a desktop app is friction rather than a feature.
Pricing, from Smallpdf’s own published comparison table: Free at $0/month, Pro at $12/month or $9/month billed yearly, which is $108 a year. Team is $10/month per seat, or $7/month per seat billed yearly with a two-seat minimum. Their public pricing page renders figures client-side and varies them by region, so the comparison table is the more quotable source; check the live page for your own currency before buying.
$108 a year is most of four years of Smol, every year, to compress files in a browser. If you are buying the whole suite that maths is different and possibly fine. If you are buying it because a PDF was too big for Gmail once, it is the worst value on this page and we would say so about our own product in the same position.
Same structural caveat as iLovePDF, and more of it, since Smallpdf’s tools tend to be used on business documents: your files transit their infrastructure. That is a contractual question for anyone working under an NDA, not a philosophical one.
Why does the same PDF compress so differently in each tool?
Almost all of the size in a bloated PDF is embedded raster images. Every tool here is doing the same two things to them: throwing away pixels, then re-encoding what is left. The differences come from three choices.
What the resolution target is measured against. Ghostscript and Preview’s Quartz filter both target DPI, so they read the placed size of each image on the page and resample to hit a resolution. Smol caps pixel dimensions instead, which is cheaper and more predictable in bytes but drifts in DPI as page geometry changes. Neither approach is wrong; they answer different questions.
Which JPEG encoder does the re-encoding. At matched resolution our Preview output was roughly 3.4 × the size of Smol’s. Same pixels, different encoder. A modern mozjpeg-class encoder buys a real double-digit percentage at identical visual quality, and it compounds across a batch.
What happens to everything that is not an image. Our text-only control file, 7,095 bytes of pure vector content, came out at 7,077 bytes. A 0.3% saving. Every tool that claims “up to 90% smaller” is describing image-heavy documents, and if your PDF is a Word export with no pictures in it, no compressor on this page will help you. The detail is in our breakdown of what each preset actually changes.
What if you have 50 PDFs, not one?
This is the question that separates the tools, and most roundups skip it. Preview via Automator can batch but overwrites in place unless you build the workflow carefully. Ghostscript batches trivially with a shell loop, at the cost of writing a shell loop. Web tools cap you at a handful of files per task and charge for more. Smol and PDF Squeezer both take a folder.
Our own number, measured: 25 copies of the brochure, 89 MB in, processed at Small in 4,230 ms, 3.67 MB out. Nothing uploaded, nothing queued. The honest caveat is that those 25 files were identical, which is the best case for CPU cache behaviour; a mixed folder of real documents will be slower.
If your batch is part of something repeatable, Smol also exposes a Model Context Protocol server, so Claude Code, Codex and Google Antigravity can drive compression directly as a tool call rather than you dragging folders around. Every measurement in this article was produced through that interface, which is a reasonable proof that it works. It is a developer feature and most readers will never need it, but if you are already scripting asset pipelines it removes a manual step.
For images rather than documents, the same logic and the same comparisons are in compressing images on Mac, every method compared, and the local-versus-cloud trade-off is worked through in Smol vs TinyPNG.
When Smol is not the right answer
Four cases, and they are not hypothetical.
You compress a PDF twice a year. Preview is free, installed, and produces a perfectly emailable file. Paying $29 to save 700 KB twice a year is not a good use of $29. We would rather you kept it.
You need a guaranteed DPI ceiling. Print vendors and journal submission systems specify resolution, not pixel counts. Smol’s presets cap pixels, so the resulting DPI varies with page size. Ghostscript with -dPDFSETTINGS=/ebook, or Acrobat’s PDF Optimizer with an explicit ppi value, enforces the thing the spec actually asks for.
You need PDF features, not smaller files. Preflight, PDF/A, redaction, OCR, forms, page reordering, digital signatures: Smol does none of it. That is Acrobat Pro’s territory and it earns its price there.
You are not on a Mac. There is no Windows or Linux build. Use iLovePDF or Ghostscript.
One more, less about Smol than about expectations: if your PDF is 400 KB of text and vector charts, no compressor will meaningfully shrink it. There is nothing lossy in the file to discard. The size is the content.
Frequently asked questions
What is the best PDF compressor for Mac?
For regular work, Smol: it produced the smallest output at every resolution we tested, batches folders, and costs $29 once. For a single PDF you need smaller right now, macOS Preview is free, already installed, and produced a 73.6% reduction on our test file. For preflight or PDF/A output, Adobe Acrobat Pro is the only option here that can do it.
Is macOS Preview good enough to compress PDFs?
For one file, yes. Preview applies the Reduce File Size Quartz filter, which resamples images to 144 PPI with a 2,400 px ceiling and re-encodes them as JPEG at quality 0.7. On our 3.56 MB test brochure that produced a 73.6% reduction in about 0.19 seconds. Its limits are that there is no quality dial and no practical batch mode without building an Automator workflow.
How much can a PDF actually be compressed?
It depends entirely on how much of the file is raster images. Our image-heavy 3.56 MB brochure went to 153,911 bytes at Smol’s Small preset, a 95.9% reduction. Our 7,095-byte text-only control file only lost 0.3%, because there is nothing lossy in it to discard. Text and vector artwork are already compact and stay untouched at every quality level.
Can I compress a PDF on Mac without uploading it anywhere?
Yes, three ways. Preview does it with File then Export and the Reduce File Size Quartz filter. Ghostscript does it from Terminal with one command. Smol does it with a drag and drop and five quality presets. All three process the file on your own machine, which matters for contracts, medical records and anything under an NDA.
Is Adobe Acrobat Pro worth it just for compressing PDFs?
No. Adobe lists Acrobat Pro for individuals at US$239.88 per year prepaid, and free or one-time tools produce comparable or smaller files. Acrobat earns that price on preflight, PDF/A conversion, redaction, forms and per-object optimization, not on compression. If those features are irrelevant to you, so is the subscription.
Why did Ghostscript make my PDF bigger?
You probably used -dPDFSETTINGS=/prepress or /printer. Both leave 300 PPI images untouched, and rewriting the document costs a few kilobytes, so the output can exceed the input. In our test /printer produced a file 0.3% larger and /prepress 0.1% larger than the original. Use /ebook for sharing or /screen for email.
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