Combining several PDFs into one file is one of the most common document tasks — merging scanned pages, assembling a report from multiple sources, or bundling invoices for submission. Every PDF tool offers merging, but they differ in how many files you can combine, whether you can reorder pages before merging, whether files are uploaded to a server, and whether the free tier has a daily cap. We tested six of the most popular free PDF mergers across these criteria. For most people a browser-based merger is ideal because the files never leave your device; for very large batches, server-based tools with generous limits are a solid alternative.
Browser-based, unlimited, drag to reorder
Criply merges PDFs entirely in your browser using pdf-lib — nothing is uploaded to a server, which makes it the safest option for confidential documents. You can combine an unlimited number of files, drag them into any order before merging, and bookmarks from the source files are preserved in the output. There is no daily cap, no signup, and no watermark. The interface is clean and works well on mobile. The trade-off versus server-side tools is that merging a very large number of large files relies on your device's memory, so extremely heavy batches may be slower on low-powered phones.
Pros
Cons
Best for: Anyone merging confidential documents who wants zero server upload
Unlimited free merging, ads included
iLovePDF's merge tool is unlimited on the free tier with no daily cap, and it handles reordering and page-level selection well. It is one of the most reliable server-side mergers, with a long operating history and a polished workflow. The free web version carries significant advertising, and all files are uploaded to iLovePDF's servers for processing (they are deleted after a short period). For users who need to merge frequently without paying and do not mind the ads or server upload, iLovePDF is a dependable choice. A mobile app is also available.
Pros
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Best for: Frequent users who want unlimited merging and do not mind ads
Unlimited, with offline desktop app
PDF24's merge tool has no usage limits, requires no account, and the Windows desktop app can merge files entirely offline — a genuine privacy benefit for sensitive work. It supports reordering and is generous with file count. The web interface is functional but cluttered, which makes it harder to use on mobile than cleaner alternatives. For Windows users who want a free local merger they can run without uploading anything, PDF24's desktop application is one of the strongest options available.
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Best for: Windows users who want unlimited offline merging
Cleanest interface, limited free use
Smallpdf has the most polished merge interface of any tool here — fast, minimal, and easy on any screen size. Reordering is smooth and the output is reliable. The limitation is the free tier: two PDF tasks per day before a subscription prompt appears. For someone who only occasionally needs to merge files, the experience quality makes that cap acceptable. For regular merging it becomes a recurring obstacle. Files are uploaded to Smallpdf's servers and deleted after one hour.
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Best for: Occasional users who want the most polished experience
Clean design, modest free limits
Sejda offers a clean, modern merge tool with a pleasant interface and a desktop version that processes files locally. It also includes light editing features that most free mergers lack. The free tier limits you to three tasks per day and files up to 50 MB or 200 pages. That makes Sejda well-suited to occasional merging where the experience matters more than volume. For heavier or larger jobs, the limits become restrictive and a paid plan is required.
Pros
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Best for: Occasional users who value clean design and some editing
Trusted brand, limited free access
Adobe's online merge tool uses the same engine as Acrobat and produces clean, reliable output with well-documented security practices. It is a trustworthy option for a one-off merge where you want the assurance of Adobe's handling. The free access is limited — typically two tasks before an Adobe account is required and further use is gated behind an Acrobat subscription. Files are uploaded to Adobe's cloud. For regular merging it is not practical without paying, but for an occasional high-stakes document it is dependable.
Pros
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Best for: One-off merges where brand trust is the priority
For most people, Criply is the best choice — unlimited, no upload, drag-to-reorder, and no signup. For frequent server-side merging without a daily cap, iLovePDF is the most practical free option. PDF24's desktop app is ideal for Windows users who want unlimited offline merging. If you only merge occasionally and want the cleanest experience, Smallpdf is worth the two-per-day limit.
Yes. Criply, iLovePDF, and PDF24 all let you merge PDFs without an account. Criply processes the merge in your browser so files are never uploaded.
This roundup was written after testing each tool. Rankings reflect our assessment of free-tier value for the stated use case — we do not accept payment for placement. Criply is our own product and is listed where it genuinely fits. Tool features and pricing change; verify current terms on each tool's website before making decisions.