Do it on GustKit
Add the PDFs
Open Merge PDF and drop two or more files. A photo or a video is refused here. If a file asks for a password, unlock it first.
Set the order
Drag the cards, or use the arrow buttons. The first card becomes the first page of the new document. Thumbnails show what you are stacking.
Merge
Press Merge PDF. GustKit copies the original pages with pdf-lib. Text stays selectable, links stay links, and pictures are not recompressed by this step.
Save and, if needed, shrink
The download is usually about as large as the inputs added together. If an email or a portal rejects that size, run the result through Compress PDF.
What the merge actually does
This is not a reprint. Each page is copied as it already exists, so a sentence you can select in the original can still be selected in the result. Vector drawings stay sharp. Photos keep the quality they had. The new file is a new container, not a scan of the old ones.
That also explains the size. Copying pages does not throw data away. A 4 MB report plus a 6 MB scan lands near 10 MB. If you wanted a smaller file, merging was only the first job. Compress PDF is the second, and it is honest about when a text-only PDF will not shrink.
Locked files, forms, and page edits
A password-protected PDF has to be opened before its pages can be copied. Use Unlock PDF on that file, then come back and drop the unlocked download with the others. GustKit tells you when it hits a protected file instead of pretending the merge worked.
Form fields are copied as they are. A form that depends on JavaScript inside the PDF can behave differently after the pages move into a new document, so open the result and try the fields before you send it. If you only needed to rotate one page, delete a blank, or pull a range out, Organize PDF and Split PDF do those jobs without stacking extra files.
A sensible order of work
Put the files in reading order before you merge. Fixing the order later means another pass. Name the download so you can tell it from the pieces: the original files stay on your device, and the merge does not delete them.
Scans of an ID, a proof of address, and a signed form are a common set. Merge them, check that every page is upright, then compress only if the portal complains about size. Strong compression turns pages into images and the text stops being selectable. Balanced compression shrinks photos and leaves text alone. Pick that on the compress page, not here.
The files stay in this tab
The PDFs are read by code in the page. After the page has loaded, you can disconnect and the merge still runs. Closing the tab drops the files from memory. GustKit does not keep a copy, and the guide you are reading is only text.
There is no account on the tool page. If the download looks wrong, the originals are still where you left them. Merge again, or split the result and keep the half you needed.
Frequently asked questions
How many PDFs can I merge?
There is no fixed count. The practical limit is the memory of the device. Phones handle a few hundred pages. Computers handle more. If the tab becomes slow, merge in two batches and then merge those two results.
Will the text get blurry?
Not from the merge. Pages are copied, not photographed again. Blur comes from a later step, usually strong compression, which re-renders each page as an image.
Can I remove a page while I merge?
Not in the same step. Merge the files you want, then use Split PDF or the organize tools to drop or rotate a page in the download.
Tools for this job
- Merge PDF Drop two or more PDFs, drag them into the order you want and download a single combined PDF. Nothing is uploaded.
- Compress PDF Choose a level, press Compress and compare the before/after size. Best results on PDFs with photos or scans.
- Split PDF Open a PDF, type the pages you need (for example 1-3, 7) or split every page, and download the new files. It all happens on your device.
- Organize PDF Drop a PDF, drag the page cards until the order is right, and save. Text and images are copied, not retyped. The file stays on your device.
- Unlock PDF Drop a locked PDF, type the password that opens it, and download a copy with the lock removed. The password is used only in this tab.
More guides
Compress and convert
How to compress a PDF without uploading it
A portal that rejects a large attachment does not care why the PDF is heavy. Compress PDF tries to make it smaller on your device. The useful part is knowing which mode matches the file you have, because the two modes do different things.
Read the guide
Open the tool: Compress PDF
Compress and convert
How to turn JPG photos into one PDF
A form that asks for one PDF does not want six separate photos. JPG to PDF makes each image a page, in the order you set, and keeps the photo data as it is. The pictures stay on your device.
Read the guide
Open the tool: JPG to PDF
Image
How to resize an image without uploading it
A form that asks for a picture under a certain width, or a page that should not ship a 4000 pixel photo, needs a resize. Resize image sets the pixel size on your device. It does not invent detail, and it does not require an account.
Read the guide
Open the tool: Resize image