Does iPhone have a built-in way to compress PDFs?

Partly. The Shortcuts app has an Optimize File Size of PDF action you can build a shortcut around. It helps a little, but it does not let you pick a target size and often barely shrinks scans.

How do I compress a PDF to 200 KB on my phone?

Open PDFToast's Compress to size tool in your phone browser, add the PDF, type 200 as the limit and download. It picks the best quality that fits under 200 KB.

Why did my PDF barely get smaller?

PDFs made from typed text are usually small already, so there is little to remove. Scans and photos shrink the most. Try a stronger mode, convert to grayscale, or remove pages you don't need.

Is compressing a PDF in the browser safe?

It depends on the site. Many upload your file to a server. PDFToast compresses inside your browser, so the file stays on your phone.

How to Compress a PDF on iPhone and Android (Free, No App)

Shrink a PDF on your phone: iPhone Shortcuts, Android apps, or a browser tool that compresses to an exact KB limit without uploading your file. Plus fixes when it fails.

The quickest way to compress a PDF on any phone is in the browser. Open Compress PDF in Chrome or Safari, add the file, pick a level and download. If a form asks for a specific limit like 100 or 200 KB, use Compress to size and type the number. Nothing to install, and the file never leaves your phone.

Checked on 15 October 2026. iOS and Android menus change between versions.

Your options at a glance

Method	Phone	Install?	Pick a target size?	Uploads your file?
Shortcuts “Optimize File Size of PDF”	iPhone	No (Shortcuts is built in)	No	No
Third-party compressor apps	Android, iPhone	Yes	Some do	Varies; check the app’s privacy policy
Most compression websites	Both	No	Some do	Usually yes
PDFToast Compress / Compress to size	Both	No	Yes, any KB	No, runs in your browser

iPhone: the built-in Shortcuts option

iOS doesn’t have a “Compress” button in Files, but the Shortcuts app includes an action called Optimize File Size of PDF. MacMost and iGeeksBlog show how to build a shortcut with it:

Open Shortcuts and tap + to create a new shortcut.
Add the Optimize File Size of PDF action.
Set the shortcut to receive PDFs from the Share Sheet, and add a Save File action at the end.
Open your PDF in Files, tap Share, and run the shortcut.

The catch: according to both guides, this action keeps high-resolution images, so the saving is often small, and already-compressed files may not shrink at all. You also can’t tell it “make this under 200 KB”. Some guides mention an Optimize File Size quick action in the Files app; if your iPhone doesn’t show it, use Shortcuts or the browser method below.

Android: what’s built in

Android has no built-in PDF compressor in Files or Google Drive. Your choices are:

An app from the Play Store. Many work well, but check whether they process files on the phone or upload them, and whether the free version adds watermarks.
A website in Chrome. No install, but most compression sites upload your file to their servers.
A browser tool that works on your phone, like PDFToast, which gives you the convenience of a website without the upload.

Step by step: compress in your phone’s browser

This works the same on Android and iPhone.

When you just want it smaller

Open Compress PDF in Chrome, Safari, Samsung Internet or Firefox.
Tap to add your PDF from Files, Downloads, Google Drive or iCloud.
Choose a level. Lossless keeps text and links exactly as they are. Stronger modes shrink scans and photos much more.
Tap Compress & download.
Check the new size in your Downloads or Files, then share it on WhatsApp or email.

When a form gives you a size limit

Open Compress to size.
Add the PDF.
Type the limit from your form, for example 200 for 200 KB.
Download a file that’s under the limit, at the best quality that fits.

Shortcuts for common limits: 50 KB, 100 KB, 200 KB, 300 KB, 500 KB and 1 MB. Need several files under one total, like Passport Seva? Use Fit files to upload limit.

The compression runs on your phone’s processor. Your file isn’t uploaded, and the tool keeps working if you lose signal after the page has loaded. Here is how to test that yourself.

Troubleshooting

“It barely got smaller”

PDFs made from Word documents or typed forms are mostly text, which is already compact. Compression has the most effect on scans and photos. Try:

A stronger compression level.
Grayscale PDF, which often makes colour scans much smaller.
Removing pages you don’t need with Delete pages.

“It’s too blurry to read”

The target size is too small for the number of pages. Options:

Raise the limit a little if the form allows it.
Remove blank or extra pages first.
Rescan text pages in black and white, which keeps letters sharp at small sizes. See our scanning guide.
Split one large file into two uploads if the portal allows several files, using Split PDF.

“The file won’t open” or “It asks for a password”

Password-protected PDFs, like bank statements and e-Aadhaar, must be unlocked before compressing. Use Unlock PDF with the password, then compress the unlocked copy. If the file is damaged, try Repair PDF first.

“I can’t find the downloaded file”

Android: open the Files app and check Downloads, or tap the download notification in Chrome.
iPhone: Safari saves to a Downloads folder in the Files app, either in iCloud Drive or On My iPhone depending on your settings. Tap the download arrow in Safari’s address bar to jump to it.

“The portal still says the file is too big”

Some portals count 1 MB as 1,000 KB and some as 1,024 KB, and some limits are total rather than per file. Aim a little under the limit (for example 190 KB for a 200 KB limit) to be safe.

“My phone is slow with a big file”

Large scans with many pages need memory. Close other apps, keep the screen on while it works, or split the file and compress each part. On the free plan, PDFToast handles files up to 50 MB per job.