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Create ZIP Archive

Bundle any set of files into a single ZIP. The archive is built in your browser, so nothing is uploaded and nothing leaves your device.

Create a ZIP archive

Bundle any set of files into a single ZIP. Everything is packed in your browser, so the files never leave your device.

The moment you zip files is the moment not to upload them

Think about why anyone makes a ZIP. Almost always it is because a set of files needs to travel: an email attachment, a form upload, a handover to an accountant, a bundle of scans for a landlord or a lawyer. The archive exists to be sent, which means its contents are, by definition, the things you were about to share with someone specific and nobody else.

That makes the usual advice to “just use an online zipper” slightly absurd on inspection. To avoid attaching twelve files to an email, you upload all twelve to a company you have never heard of, wait while their server compresses them, and download the result. The files have now been somewhere you did not intend, in exactly the case where you were being deliberate about where they went.

This page does the compression where the files already are. The ZIP format is well documented and the deflate algorithm is decades old; there is no technical reason the work needs a server, and the only reason it usually gets one is that running code on someone else’s machine used to be the easy way to build a website.

Why the compression setting is not just a speed dial

Deflate finds repetition and replaces it with references. Text, spreadsheets, logs, source code and uncompressed images are full of repetition, so they shrink dramatically, often to a third of their size or less. That is the case the default is tuned for.

A JPEG, an MP4 or a PDF has already had that treatment applied by its own format. Running deflate over it again finds almost nothing left to exploit, so you spend the processing time and get back a percent or two, and occasionally a file that is marginally larger than it started. This is why the tool watches what you have added and suggests storing rather than compressing when your selection is mostly media: the honest answer is sometimes that compression has nothing to offer.

What a ZIP does and does not protect

A ZIP bundles and shrinks. It does not, on its own, protect anything. An archive with no password is readable by anyone who gets hold of it, and the entry names are visible without even decompressing the contents, so a file called divorce-settlement-draft.pdf announces itself from inside a sealed-looking archive.

If the point is confidentiality rather than convenience, the ZIP is the wrong layer to solve it at. Encrypt the files or the transport instead, and treat the archive purely as what it is: a way to make many things into one thing.

Create ZIP FAQ

Are my files uploaded anywhere to make the ZIP?

No. The archive is assembled by JavaScript running on your own machine, and the finished ZIP is handed straight to your browser's downloads. No file, filename, or byte of content is sent to us or anyone else. This matters more here than for most tools: people usually zip a set of files precisely because they are about to send them somewhere, and those sets tend to contain exactly the documents you would least want sitting on a stranger's server.

What compression level should I pick?

Balanced is the right answer almost always. Pick Smallest if the archive is going somewhere with a tight size limit and you do not mind waiting. Pick Store only when the files are already compressed formats such as JPEG, MP4, PDF or other ZIPs, because deflating those again spends real time to save a fraction of a percent. The tool notices when most of your files are in that category and says so.

What happens if two files have the same name?

They get numbered, so second-copy.txt becomes second-copy (2).txt inside the archive. A ZIP has no way to hold two entries at the same path, and tools disagree about what to do when they meet one, with some showing the first, some the last and some refusing to open the file. Renaming up front means the archive contains exactly what the list on screen showed you.

Is there a limit on how many files or how large they can be?

There is no limit imposed by us, because there is no server to impose one. The real ceiling is your device's memory, since the files and the finished archive both have to fit in it at once. A few hundred megabytes is comfortable on a normal laptop; several gigabytes may not be. If the tab runs out of memory it will tell you rather than producing a truncated archive.

Do folder structures survive?

Files are added at the top level of the archive, using their own names. Browsers hand a dropped folder to a web page as a flat list of files rather than as a tree, so the nesting is not something this page can see, let alone preserve. If the structure matters, zip the folder with your operating system's own right-click option instead.