Convert ZIP to 7z Online
Drop a .zip and download the same files as a .7z archive, compressed by the 7-Zip engine in your browser.
How to convert ZIP to 7z online
- Drop the
.zipfile onto the box above, or click to choose it. - Type the password if the ZIP is encrypted. The files are unpacked and compressed again as 7z on your device.
- Save the
.7zwhen the download appears. The progress bar has a cancel button if it is taking longer than you want.
Why turn a ZIP into a 7z?
The usual reason is size. The 7z format generally compresses tighter than ZIP, which helps when an archive is just over an attachment limit, when you pay for storage, or when you are archiving project folders you rarely open.
How much you gain depends on the contents. Text, source code, databases and uncompressed images can shrink a lot. Photos, video, music and PDFs are compressed already, so the 7z will be about the same size as the ZIP, and converting is not worth the wait.
Slower than a desktop app
The compression is done by 7-Zip compiled to WebAssembly, running inside your browser tab on a single thread. A desktop archiver uses every core of your processor; this page uses one. Converting a small or medium ZIP is fine. For many gigabytes, expect a long wait, and consider a desktop program if you do this regularly.
In exchange, nothing leaves your device and there is nothing to install.
Limits worth knowing
The converted 7z is not encrypted, even if the ZIP had a password. To make a 7z with AES-256 and hidden file names, extract the ZIP and build a new archive with the 7z creator.
Unix permissions and symbolic links stored in the ZIP are not carried over. Remember too that the person receiving a 7z needs software that opens it, or a page like the 7z extractor.
Frequently asked questions
How much smaller will the 7z be?
It depends on what is inside. Text-like files often shrink considerably compared with ZIP. Files that are already compressed, such as JPEG, MP4, MP3 or PDF, barely change.
Why is the conversion slow?
7z compression in a browser runs on one processor core, and the conversion happens entirely on your device. It is noticeably slower than a desktop app, and a large archive takes as long as your device needs.
Can I add a password to the 7z during conversion?
No. Converted archives are not encrypted. Use the 7z creator on this site to build an archive with AES-256 encryption and encrypted file names.
Can it convert ZIP to RAR instead?
No. RAR is a proprietary format that cannot be created here. 7z is the open alternative with comparable compression.
Is my ZIP uploaded?
No. Both the unpacking and the 7z compression run locally in your browser. No file data is sent anywhere.