Merge PDF online — free, fast and private

Combine multiple PDF files into one. With Pixpoo you can merge PDF online for free, right in your browser — no sign-up, no watermark, and your files are processed locally rather than sent to Pixpoo’s servers.

About Merge PDF

Merging a PDF means taking two or more separate documents and joining them into a single file, with the pages laid end to end in the order you choose. Nothing is flattened into images or re-encoded, so text remains selectable and searchable, vector graphics hold their sharpness at any zoom, and embedded fonts travel with the pages that use them. Note that Page Size opens on A4 rather than Original, so unless you change it, each page is placed onto a standard sheet with a margin rather than kept at its own dimensions — still as vector content, but scaled and centred. The optional Grayscale and Enhance Contrast settings are the one exception — they redraw each page as an image, which is covered under the options below.

The reason it comes up so often is that documents rarely arrive in one piece. Software exports a section at a time, scanners save a file per page, and paperwork accumulates as separate downloads over weeks or months. Almost everything downstream, though, prefers a single file — email attachments, upload forms, printers and archives are all simpler to handle when there is one document rather than twelve. Merging is the step that closes that gap.

A few things are worth knowing before you merge. Page order is decided entirely by the order of the files in the list, so arrange them before you combine rather than after. Pages of different sizes and orientations can live in the same PDF quite happily — an A4 report followed by a landscape spreadsheet page keeps both dimensions — so you do not need to normalise anything first. Interactive elements behave less predictably: bookmarks, form fields and annotations belong to their original document, and while page content always survives, complex interactive layers may not carry over intact. If a source file is password-protected, remove the password first, because an encrypted PDF cannot be read for merging until it is unlocked.

When should you merge PDF files?

Merging is worth doing whenever several files really belong together as one document. The most common cases:

• Combining scanned pages — a scanner that saves one file per page, reassembled into a single document
• Putting invoices, receipts or statements into one monthly or quarterly file
• Joining a report to its appendices, exhibits or supporting data
• Submitting several documents where a portal or e-filing system accepts only one PDF
• Grouping related paperwork — a contract with its annexes, an application with its evidence — before sharing
• Preparing a set of documents for printing or long-term archiving as one file

Merge PDF options explained

Every setting in the Merge PDF panel changes the merged document in a specific way. Here is what each one does and when it is worth switching on.

Grayscale

Converts every page in the merged document to black and white, discarding all colour information. It is applied to the output only — your source files are untouched.

Turn it on when you are combining colour scans that only need to be legible, not decorative. Removing colour typically cuts the file size of a scanned document substantially, gives pages from different scanners a consistent look, and prints predictably on a mono printer. Leave it off if any page carries meaning in its colour — a chart with a colour key, a highlighted clause, or a signature you want to prove was signed in blue ink. One trade-off to know about: applying Grayscale redraws each page as an image at 150 DPI rather than recolouring it in place, so text on those pages stops being selectable and searchable and very fine detail is softened. Use it when legibility and file size matter more than keeping the text layer intact.

Enhance Contrast

Pushes dark pixels darker and light pixels lighter, so faint text separates from the background instead of blending into it.

This is the one to reach for with old or tired scans: faded thermal receipts, a photocopy of a photocopy, pencil annotations, or a document photographed in poor light where the page reads grey rather than white. It is deliberately a single toggle rather than a slider, so there is nothing to tune. Avoid it on pages containing photographs — the same push that rescues faint text will crush the subtle mid-tones a photo depends on. Like Grayscale, this effect is painted into the page: those pages are redrawn as 150 DPI images, so their text is no longer selectable. That is a fair trade for a scan that was already an image, but not for a text PDF that reads perfectly well as it is.

Page Size

Chooses the sheet size for the merged document. Original keeps every page at whatever size it already was; A4 (21 × 29.7 cm), Letter (21.6 × 27.9 cm) and Legal (21.6 × 35.6 cm) scale every page onto one consistent sheet.

Original is the right default when you simply want the pages joined and intend to read on screen. Pick a fixed size when the merged file will be printed or submitted somewhere — a document that alternates between A4 and Letter pages comes out of a printer with inconsistent margins, and many application portals and e-filing systems expect one standard size throughout. Note that scaling a page to a sheet of a different shape adds padding at the edges rather than stretching the content, so nothing is ever distorted.

Page Orientation

Sets whether the chosen page size is used tall (Portrait) or wide (Landscape). It works together with Page Size, so it has no effect while Page Size is set to Original.

Portrait suits almost every text document. Switch to Landscape when the content is wider than it is tall — merged spreadsheet exports, wide financial tables, Gantt charts, or slide handouts. If only some of your pages are wide, it is usually better to leave Page Size on Original so each page keeps the shape it was designed for, rather than forcing the whole document one way.

Margin

Adds white space around each page as it is placed onto the merged sheet. None places the page edge to edge; Small, Normal and Large add progressively more padding.

Normal is a safe default for anything that will be printed, because most desktop printers cannot print right to the paper edge and will clip content that sits too close to it. Choose Large when the document will be hole-punched or bound, so the binding does not swallow text. Choose None when you want the scan reproduced exactly as captured, or when the source pages already carry generous margins of their own and more padding would just shrink the readable area.

Add Blank Page Between Files

Inserts one empty page after each source file, so every document in the merge begins on a fresh page.

The main reason is double-sided printing. Without it, the last page of one document and the first page of the next can end up on two sides of the same sheet, which is confusing when the stack is separated later. It is also useful when you are merging several distinct documents — contracts, invoices, chapters — and want an obvious visual break between them rather than one continuous run of pages.

Reordering pages

Selecting a page in the preview and using Move Up or Move Down shifts it one position at a time. You can also drag a page thumbnail straight to where you want it.

Use dragging for a big rearrangement and the buttons for a precise, single-step nudge — dropping a page exactly between two neighbours is fiddly by hand. This works at page level, so you can interleave pages from different files rather than only reordering whole documents. Every move is covered by Undo and Redo, so it is safe to experiment before you merge.

Insert blank page

Select any page in the preview, then add an empty page immediately before or after it.

This is the manual counterpart to the automatic blank-page toggle, for when you need a break in one specific place rather than between every file. Typical uses are forcing a section to start on a right-hand page in a double-sided print run, leaving a deliberate gap for a signature page that will be added later, or giving a reader space to write notes after a particular section.

Why use Pixpoo for Merge PDF?

• No fixed file-count limit — the practical ceiling is your device’s memory, not a quota
• Drag-and-drop reordering with page thumbnails, so you can see what you are arranging
• Nothing is uploaded — the merge happens on your own machine, not on Pixpoo’s servers
• No sign-up, no email, no watermark stamped on the result
• Copies pages as they are by default, so text stays selectable and searchable
• Works the same on Windows, macOS, Linux, Android and iOS with nothing to install

Merge PDF features

Merge PDF limitations

Pixpoo preserves normal PDF page content without re-encoding by default. Some interactive PDF elements, such as bookmarks, form fields and annotations, may not survive the merge exactly as they were in the source files. Grayscale and Enhance Contrast also redraw pages at 150 DPI, which removes selectable text from those processed pages. Password-protected PDFs must be unlocked before they can be merged.

Common Merge PDF questions

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