Merge PDF
Merge PDF is your one-stop tool to gather several documents into a single file: combine contracts, scans, reports or book chapters and get one clean PDF. A visual canvas shows every page thumbnail — drag to reorder, untick what you don't need. Everything runs locally in your browser — files never leave your computer.
When do you need it?
- Combine scanned pages and the electronic copy of one document.
- Join several parts of a single report or presentation before sending.
- Assemble an application: cover sheet, CV, appendices.
- Stack a month of invoices into one file for accounting.
Key features
- A canvas with every page thumbnail — drag & drop reordering.
- Checkbox page selection — skip the pages you don't need.
- Multiple files at once with no page limits.
- 100% on-device processing — private by design.
How to use
- Upload or drag & drop your file — everything runs right in your browser.
- Pick your options and hit the process button.
- Download the result — fast, free, no account required.
Safety & privacy
All PDFs are opened and merged right in the browser with pdf-lib. No files are uploaded or stored. Sensitive documents never leave your device.
Genuinely free — no limits
KitsyApp is 100% free — no signup, no daily limits, no watermarks. Processing quality is on par with paid tools like Smallpdf or iLovePDF, and your files are processed on your own device instead of someone else's server.
Merging PDFs: a practical guide and common mistakes
When do you actually need to merge PDFs?
Merging is used more often than it is actually needed. Three cases where it is the right call: you have to send one complete document (an application with attachments, a contract with annexes), you need to print several files as one continuous job, or you are archiving and want loose parts combined into a single record.
If you only need a few pages out of several files for reference, do not merge — extract the pages instead. Once merged, splitting back to the original boundaries is hard, especially when each file carries its own page numbering.
Merging in three steps
- Drag and drop all the files at once (or click to select several).
- Reorder by dragging each file — the on-screen order becomes the order in the output.
- Merge and download. Everything runs in your browser; nothing is uploaded to a server.
Six mistakes people make when merging
- Mixing page sizes: A4 together with Letter scans throws off print margins and leaves extra white edges. Normalise the page size first.
- Merging compressed files with originals: output quality follows the weakest input, so compress AFTER merging, not before.
- Forgetting to check page order: the result keeps your drag order — it does not sort by filename.
- Merging password-protected files: a locked file blocks the whole job. Unlock it first.
- Merging sideways scans with upright ones: you get landscape pages in the middle of portrait ones. Rotate before merging.
- Naming the output carelessly: use a name that says what it is (contract-2026-annexes.pdf) so you can find it later.
Does merging reduce quality?
No. Merging only rearranges the existing pages into a single structure — no image recompression, no re-rendering, no intermediate format conversion. Text stays vector data and images keep their original resolution. That is why you should merge BEFORE compressing: you lose image data once, at the last step.
Merging on a phone
No app required. Open the tool in your phone browser and it works immediately, even when the files live in another storage app — just multi-select in the file picker. One practical note: with very large files (hundreds of MB), a phone can run out of memory while processing; merge in smaller groups, then merge the groups.
Frequently asked questions
Can I change the page order before merging?
Yes. Every page on the canvas is a draggable card. Filename sort and reverse are also available.
Can I leave some pages out?
Of course. Untick unwanted pages and they won't appear in the final file.
How many files can I merge at once?
There is no hard limit on file count. The practical limit is your device's memory: on a typical laptop, a few dozen files of a few dozen MB each is normal. If it feels slow, merge in smaller groups and then merge the groups.
Can I split the merged file back exactly as it was?
You can split it back by page number, but the boundaries between the original files leave no trace — unless you remember exactly which pages came from which file. Note the order before merging if you may need to split again later.
Does the merged file get a watermark or stamp?
No. The output is clean and keeps each page's original content. No watermark, no inserted cover page, no automatic page numbers.
Do I need an account to merge?
No. No signup, no limit on how many times you can merge, no file limit — and no paid tier hiding the feature you need.