How to Merge and Compress PDFs on Your Phone | Done Entirely with a Free App
Want to combine scattered PDFs — contracts, invoices, reference material — into one file? Or shrink a PDF that's too large to attach to an email? You can solve both without a computer, using only a phone app.
When You'll Want to Merge PDFs
When you scan paper documents one page at a time, you can end up with a separate PDF file for each page. Submissions to government offices or business partners are often specified as "please combine into one PDF," which makes merging necessary.
Steps to Merge PDFs on Your Phone
- Open PDF Toolkit
- For paper documents, photograph them with "Scan to PDF," which automatically corrects and converts them into a PDF
- Select the multiple PDFs you have, then combine them into one with "Merge PDFs"
Images you already have saved as photos can also be combined into a single PDF using "Create PDF from Images."
How to Compress a PDF to Reduce File Size
If a PDF won't send over email or LINE, you can shrink its file size with the "Compress PDF" feature. PDFs containing a lot of photos or charts tend to see a bigger reduction.
When You Need to Split a PDF
Conversely, if you only need part of a PDF, "Split PDF" lets you cut it out by specifying a page range or interval. Since the app handles both combining and splitting, it covers document organization from start to finish.
What to Look for When Choosing an App
- Is it free to use (any per-use charges or ads)?
- Do scanning, merging, splitting, and compressing all work in one app?
- Can you search and copy scanned text (OCR support)?
- Does it support Japanese?
Rather than switching between multiple apps, sticking to a single app that covers everything means less to learn.
Features Added in Recent Updates
Through updates, PDF Toolkit has added an OCR feature that recognizes scanned text so it can be searched and copied, page rotation, an extraction feature that pulls out just the pages you need into a new PDF, a feature to share PDF pages as images, and a feature to add a handwritten signature or notes. Beyond merging, splitting, and compressing, this one app now covers a much wider range of document tasks.
PDF Toolkit
Scan, merge, split, compress, and OCR text recognition — all in one app. Free, with English support.
📲 Download for free