How to use the unzip files online
- Choose a ZIP file or drop it on the box. Archives up to 100 MB are accepted. The file is opened on your device and is never uploaded.
- Read the table of files. Each row shows the path inside the archive, the size when unpacked, and a tag if the file is password protected, too large or looks like a program.
- Press Download on a row to unpack just that file, or tick several rows and press Download ticked files.
- Open the downloaded files with the app that suits their type. If a file fails its checksum, the tool says so rather than handing you damaged data.
What the table shows
An archive might hold four items: a text file a.txt of 600 bytes, a folder named dir, a file dir/b.bin of 256 bytes and a file named ΓΌ.txt of 7 bytes. The summary then reads 3 files, 1 folder and 863 bytes unpacked. Folders get no download button because they hold no data of their own.
Each file is checked against the CRC-32 value stored in the archive. For the 600 byte text file the stored value is 2521617117, and the unpacked bytes must produce the same number or the tool refuses the file.
How a ZIP file is read
A ZIP archive ends with a directory that lists every file, where it starts, how it was compressed and its checksum. The tool reads that directory first, so you see the full list without unpacking anything. When you ask for a file, only that file is decompressed, which keeps memory use low for big archives.
The tool does not trust the sizes written in the archive. While unpacking, it counts the real output and stops if it grows beyond the declared size or the limit of 100 MB for one file. This protects your browser from archives built to expand into huge amounts of data.
Safety notes
Nothing in the archive is run, opened or shown as a web page. File names are displayed as plain text, and folder parts are removed from the download name so a name such as ../../file cannot point anywhere. Files that look like programs, such as .exe, .bat or .js files, carry a tag. Unpacking them is safe, but running them is not something to do unless you trust whoever sent them.
Password protected entries, the ZIP64 format for huge archives, and other archive types such as RAR or 7z are not supported. To make an archive use the ZIP file creator, to check what kind of file something really is use the file type identifier, and to look at raw bytes use the hex viewer.
Assumptions and limits
- Only the Stored and Deflate compression methods are supported, which covers the great majority of ZIP files.
- File names that are not marked as UTF-8 are read as Windows-1252, so unusual characters may look different from the original.
- Up to 5,000 entries are listed, and up to 400 MB can be unpacked in one batch of ticked files.
- Dates are not shown, and file permissions in the archive are ignored.
Frequently asked questions
How do I open a ZIP file without installing anything?
Choose the ZIP file here. The files inside are listed in your browser, and you can download any of them one at a time or tick several and download them together.
Is it safe to unzip a file from an unknown sender?
Unpacking in your browser does not run anything. The risk comes from opening or running what you take out, especially programs, so only open files you trust. Program files are tagged in the list.
Why does it say a file failed its checksum?
Each file in a ZIP has a stored CRC-32 value. If the unpacked bytes do not match it, the archive is damaged or was changed, so download it again from the source.
Can it open a password protected ZIP?
No. Encrypted entries are marked as password protected and cannot be downloaded here. Use the program that made the archive, with the password you were given.