Create a zip file online, in your browser

Q: Can I create a zip file online for free?

Yes. Open [ZipTool](/), click **Create zip**, add your files or a folder, name it, and download the `.zip`. There is no account, no install, and no upload — compression runs in your browser. Creating zips is free.

Q: Can I zip a whole folder and keep its structure?

Yes. Use **Add folder** (or drag a folder onto the dropzone). The folder is walked recursively and every file inside is stored with its relative path, so the subfolder structure is reconstructed when the archive is later extracted.

An "online zip creator" is a web page that takes your files and produces a .zip you can download — no app to install. Most such sites work by uploading your files to a server, compressing them there, and sending the archive back. ZipTool does it the other way: the compression runs entirely in your browser, so your files are packaged on your device and never transmitted anywhere. (On macOS you also have the built-in Finder method — see how to create a zip file on Mac for when each is better; on Linux, see how to create a zip file on Linux.)

To make one, open ZipTool and click Create zip in the toolbar. Drag files onto the dropzone (or pick them, or add a whole folder), name the archive, and click create — the .zip downloads and your input never leaves the tab. There is no account and no upload queue, because there is no server doing the work.

How an online zip creator works

A zip creator is the mirror image of a zip viewer: instead of reading an archive, it writes one. You give it a list of files (and optionally folder paths); it compresses each entry and assembles a single .zip with a central directory at the end that lists everything inside.

In ZipTool that assembly happens locally through zip.js, the same library used to read archives. Your browser reads each file from disk into the page, compresses it with the standard deflate method, and writes the bytes into an in-memory blob that is then handed to you as a download. No upload step exists in this flow because there is no backend to receive one. To read archives instead, see the online zip file viewer.

Step-by-step: create a zip online

Open the tool in a modern browser (Chrome, Firefox, Safari, or Edge all work). Then:

1. Click Create zip. The button lives in the toolbar at the top of the tool page. A builder panel opens with a dropzone.

2. Add your files or a folder. Drag files onto the dropzone, click it to pick individual files, or use Add folder to include a whole directory. When you add a folder, its internal structure — subfolders and relative paths — is preserved inside the archive, not flattened.

3. Name the archive. The default is archive.zip; type any name you like and the .zip extension is added for you.

4. Click Create. Each file is compressed in your browser and a single .zip is produced. A progress bar tracks the overall bytes as it runs.

5. Download (and optionally preview). The archive downloads automatically. If you leave "open in workspace" checked, the freshly built zip is also loaded into the viewer so you can browse and preview what you just made.

What is preserved inside the zip

A zip is more than a bag of files — the structure matters, and the browser builder keeps it intact.

Folder structure — add a folder and its subfolders are stored with their relative paths, so extracting later reconstructs the original tree rather than dumping a flat list.
Filenames and paths — names are kept as-is, with path separators normalized for cross-platform extraction.
Standard compression — entries use the zip default (deflate), which shrinks text, code, and documents dramatically while leaving already-compressed files (photos, video, existing zips) close to their original size. See what affects the size of a zip file for the detail.

Why "online" does not have to mean "uploaded"

The phrase "create a zip online" raises the same worry as "unzip online": if it runs in a browser, are my files being sent somewhere? For most online zip makers the answer is yes — you upload the files, a server compresses them, and the result comes back. That is a real problem when the contents are confidential: client work, source code, contracts, HR records, or anything your data-handling policy forbids putting on a third-party server.

ZipTool is built the other way. The page loads into your browser, and all the compression work happens in the tab against files held only in memory. Nothing about your input is transmitted, stored, or handed to a third party. You can prove it: open DevTools, watch the Network tab while you build a zip, and you will see no request carrying your files leave the page — then disconnect from the internet and build another zip, which still works. The broader security and privacy explainer sets out what client-side processing does and does not protect — including the confidentiality angle of building an archive that never leaves your browser.

Honest limits

A browser-based zip creator is genuinely useful, but it has real bounds worth knowing before you rely on it.

Things to keep in mind:

Browser memory is the ceiling. The tab must hold your input files and the finished archive in memory, so very large inputs — typically past a few hundred MB to the low GB range, depending on your machine — can get slow or fail. For a folder of source or a batch of documents it is effortless; for a multi-gigabyte backup use a desktop tool.
No password / encryption. The browser builder produces a standard unencrypted zip; it does not add a password. If you need the archive protected, create it here and then encrypt it with a desktop tool using AES-256 — see how to password-protect a zip file. Avoid the weak ZipCrypto scheme.
Deflate only. It writes standard .zip with deflate compression, not .7z, .tar.gz, or LZMA. That is the most compatible choice (every OS opens it natively), but not the one with the smallest possible output.
It is a creator, not an extractor or editor. You build new archives from files; you cannot open an existing zip, edit entries in place, or convert between archive formats. For browsing and previewing existing archives, use the viewer.

Frequently asked questions

Can I create a zip file online for free?

Yes. Open ZipTool, click Create zip, add your files or a folder, name it, and download the .zip. There is no account, no install, and no upload — compression runs in your browser. Creating zips is free.

Do you upload my files when I create a zip?

No. Your files are compressed entirely in your browser by zip.js and packaged into a .zip locally; nothing is transmitted to a server, stored, or handed to a third party. You can confirm it in DevTools (the Network tab shows no upload of your files) and by building a zip with the internet disconnected, which still works.

Can I zip a whole folder and keep its structure?

Yes. Use Add folder (or drag a folder onto the dropzone). The folder is walked recursively and every file inside is stored with its relative path, so the subfolder structure is reconstructed when the archive is later extracted.

Can I password-protect the zip I create?

Not in the browser builder — it produces a standard unencrypted zip. To protect the archive, create it here and then encrypt it with a desktop tool (7-Zip on Windows, Keka on macOS) using AES-256. See how to password-protect a zip file; avoid the weak ZipCrypto scheme that older tools default to.

What's the largest zip I can create?

There is no server limit because there is no server — the bound is your browser tab's memory, which must hold the input files and the output archive. Small-to-medium inputs (tens to a few hundred MB) are effortless; inputs approaching or past the low-GB range can get slow or fail. For very large archives, use a desktop tool like 7-Zip or the zip command line.

Does it work on mobile?

Yes — the builder runs in modern mobile browsers, so you can create a zip on a phone or tablet with the same no-upload behavior. Mobile memory is lower than desktop, so very large inputs are more likely to be slow or fail.