Repacks a 7z archive into a ZIP. 7z is open and excellent, and still nothing opens it out of the box — not Windows Explorer, not Finder. This gives you a file that both do, without installing anything on a machine you may not control.
7z is the best of the three, and that is the problem
It is also free and open, unlike RAR. The only thing it lacks is being installed already, and that turns out to matter more than any of the rest — particularly on a work laptop where you cannot install software.
The ZIP will usually be larger
RAR and 7z both compress harder than ZIP — 7z in particular, with LZMA2 and solid blocks that let it find repetition across files rather than within each one. Repacking into ZIP gives up that advantage, typically by 10–30% on mixed content and much more on something like source code.
What you get back is a file that every operating system on earth opens by double-clicking it. If the contents are already compressed — photos, video, music — the difference will be small, and the “store without compressing” option makes the repack much faster.
What is kept and what is not
The folder structure is kept, including nesting. Files are written back under the same paths they had inside.
What does not survive the change of container is everything Unix-specific: file permissions, ownership, and the executable bit. ZIP can store some of that and most Windows tools ignore it, so relying on it would be worse than saying plainly that it is gone. Symbolic links are skipped rather than turned into broken files, and you are told which ones.
Paths inside archives are not trusted
../../.ssh/authorized_keys. Extractors that join that onto a destination folder write outside it, which is a real and long-standing class of attack.
Nothing here writes to your disk, so the archive cannot reach anything on your machine. But the ZIP produced would carry the traversal onward to whatever unpacks it next, so entries with escaping paths are dropped and named in the result rather than passed along.
The same reasoning is behind the ceilings on entry count and unpacked size: an archive that expands to a hundred times its size is a decompression bomb, and stopping is the correct response.
Other names for this
Also searched as “7zip to zip”, “7-zip to zip”, “convert 7z”, “open 7z”.
Questions
- Is my archive uploaded?
- No. It is opened and repacked inside this tab. An archive is usually the whole of something — a project, a case file, a set of photographs — so uploading one to a converter hands over all of it at once. Turn your Wi-Fi off before you start and this still works.
- Can it open password-protected archives?
- Yes — enter the password in the options. Encrypted entries are otherwise skipped and you are told how many. The password is used here and never sent anywhere, which is the whole argument for a local tool: uploading an encrypted archive together with its password to a stranger’s server defeats the encryption entirely.
- How much bigger will the ZIP be?
- Commonly 20–40% on text and source code, where 7z’s solid compression has the most to work with. Much less on photos, audio and video, which are already compressed.
- Does it handle solid archives?
- Yes. Entries in a solid archive must be read in order, which is what happens here — so it works, but a large solid archive takes longer than a non-solid one of the same size.
- Is there a size limit?
- Your device’s memory, and a deliberate ceiling of 2 GB unpacked and 20,000 files. Those are not commercial limits — they are the point past which a browser tab stops being the right tool, and past which the file is more likely to be a decompression bomb than a real archive.