How to Reduce PDF File Size Without Losing Quality

“You can’t upload files larger than 25MB”. I’ve had this error way too many times while attaching PDFs in my Gmail. And not just this, there are several other reasons to compress a PDF file, like when I have to upload some documents on a government website and it only accepts PDF less than a certain size.

If you were to send a normal picture in JPEG, most servers (like Facebook and WhatsApp) automatically compress those files and reduce quality. PDF uses a lossless compression technique which maintains the quality and the key information which is essential for keeping the original formatting intact. Thankfully, you can always compress a PDF file. And while there is no shortage of PDF compressors. I have listed five methods that would help you compress your PDFs and make it easier to store and share over emails.

Read: Compress iPhone videos for Email and Whatsapp

Before we jump into the different methods, let’s first understand, how PDF compression works. So, PDF quality is measured in DPI (dots per inch) and to ensure the best quality you need to choose the optimal size. Now If I have a PDF that just contains general information which I’ll only view on my computer screen, 72 DPI is the minimum quality that would ensure the smallest PDF size. Ebooks are usually around 100-150 DPI and are optimal for most text-based PDFs. Anything more than 200 DPI is not recommended, as most computer screen can’t view them anyway. That said, let’s take a look at different methods to compress Pdfs with different apps and tools.

Reduce PDF File Size Without Losing Quality

Method 1: Compress them in the source of origin

First and the most obvious solution is that you compress the files while you’re creating PDFs in the first place. You get the ability to create PDF on computers and most smartphones and we seldom pay attention to the size. Acrobat Reader has an inbuilt option to optimize the PDF for the web and automatically adjusts DPI for maximum efficiency.Adobe Acrobat Reader window
Illustrator, Adobe Acrobat, and so many other applications offer PDF creation due to format’s versatility while exporting the file to PDF format you can set the parameters which can reduce your file’s size considerably so you won’t have to go back to a PDF compressor. You can reduce the size while saving by following these steps. Simply go to File > Export > save for web.

While this lets you control each aspect of compression, you can’t always rely on this because you don’t always make pdf, sometimes you just receive large PDFs.

Method 2: Online Tools

When you get the error that your PDF file is too big for the mail or that web portal, you’re just a tab away from compressing your files. There are several online PDF compressing websites that do it for free. You just have to search for the PDF compressor and click the very first result, really, it’s that simple. I found PDFresizer.com (works on smartphones as well) best for this job. It offers multiple solutions like, convert, split, merge, crop, rotate, and resize. Drop your PDF and press the button and your PDF is uploaded and you can choose the quality by adjusting the dpi. It shows the compressed size and you can download your compressed PDF file on your computer.

According to their privacy policy, all uploaded PDF documents are automatically deleted in 1 hour, so you may not want to upload any private pdf files on their servers.

pdfresize.com window

PDFresize achieved a compression of only 20% but also increased the size of a smaller PDF that I tried to compress which was already compressed.

In general, it works well for smaller files where compression is easy, however, you can’t really control the quality using this method and your data may be at risk. We only recommend this method, when no other option is available.

Method 3: Use PDF Compressor Apps

The Next most convenient way to compress PDF is to use an application. These are a well-built piece of code that does the job effectively and without any hassle. I found a couple of apps for each platform and have listed the best one of the lot for each category. These applications compress your Pdfs and optimize for various portals and websites.

For Windows, NXpowerlite is a free PDF compressing software for windows that lets you compress with up to 95% compression. It achieved a compression level of 72% which is better than most software available, though they claim up to 95% compression level. 72% isn’t bad and actually saves a lot of data when you have a few too many files to compress.

If you are a Mac user, you don’t have to download any third-party app. To compress PDF on Mac you can use the native Preview button. Start with making a copy of your PDF file (the document will replace the original one), next, open the PDF inside Preview, next head to File > Export > from the “Quartz-Filter” drop-down menu select “Reduce File Size” option and click the “Save” button.

For smartphones, Compress PDF takes the cake for mobile tools. It is the best app for both Android and iOS combined. It compresses your PDFs files instantly and lets you share it over emails, Whatsapp, and cloud.

NX compressed with 72% compression

Method 4: Zip multiple PDFs

If you’re working on multiple projects and have a batch of files to compress. Instead of compressing each file individually, you can archive all the files and compress the entire folder. The files would be significantly compressed without losing any data to the compression. You can also password protect the Zip archive.

Also Read: Try these WinRAR alternatives for Mac

Though PDF itself can be password protected, it makes sense to lock the entire building instead of individual rooms. Windows and Mac have inbuilt Zip archiving tools, but there are more advanced tools available online. Rarzilla, WinRar, and 7-zip are some of the most popular archive tools that are available which compress your files with ease.
While these tools are available on Windows and Mac but there are plenty of apps for Android and iOS.
iZip works best on the iOS and WinZip on Android.

zip convert tool windows

I compressed a bunch of Pdfs and the size before that was 20MB. Compressing the files using ZIP archiver compresses the files into one file of around 16MB which isn’t a lot but you’ll get comparatively faster uploads than uploading 20 individual Pdf files.

Method 5: Finally, check for Redundancy

I shouldn’t even call it a method, it’s just that sometimes while creating PDF we insert the same file multiple times which in turn increases the size of the PDF. Check your file any redundancies and useless info which may be taking up space in your file.

While it saves you the hassle of using other methods, doesn’t make significant changes

Which is the best way to reduce PDF file size?

There is always more than one way to a problem but the most common solution is looking twice, Method 5 is all about clearing redundancies. While you can always use online tools but I don’t rely on that due to their sketchy interface, though some of them are really good. I would suggest if you’re creating documents use Method 1 to compress your files or you can use applications that are developed specifically for this purpose. Tell us your preferred way of compressing files.

About Kaushal

Human. Writes about Tech. Dreams about Space.