Guides
How to Compress Files
Compressing files well means picking the right format and settings for what you're compressing, not just clicking the highest setting available.
Get an archive tool for your computer
Download the installer and start opening RAR, ZIP and 7z archives in a few minutes.
Choosing a format
- ZIP — the most universally supported format; a safe default for sharing with others.
- RAR — requires WinRAR or a RARLAB tool to create, but offers a recovery record and strong compression; see how to create a RAR file.
- 7z — free and open to create, generally strong compression, but less universally supported for opening than ZIP.
Compression levels
Most tools offer a range from "store" (no compression, just bundling) up to a maximum setting. Higher levels take longer and use more memory, and the size benefit shrinks the closer you get to the top of the range.
What compresses well and what doesn't
| File type | Compresses well? |
|---|---|
| Plain text, source code, logs | Yes, often substantially |
| Office documents, PDFs | Somewhat, depending on content |
| JPEG, MP3, MP4, most video/audio | Little to no further benefit — already compressed |
| Raw/uncompressed images or audio | Yes, often substantially |
Splitting for email or upload limits
- 1Check the size limitLook up the sending or upload limit for your email provider or destination.
- 2Enable volume splittingMost archive tools let you set a fixed size per part when creating the archive.
- 3Send or upload all partsThe recipient needs every part in the same folder to extract successfully.
Encrypting your archive
If the contents are sensitive, set a password when creating the archive. This typically applies AES encryption to the contents, though not always to the file list itself unless the tool offers filename encryption specifically. See password-protected RAR files.
Verifying your archive
After creating an archive, most tools offer a "test archive" option that checks its internal integrity without fully extracting it, which is a quick way to confirm the archive isn't corrupted before you send or store it.
Download and try it yourself
Install the archive tool and apply the steps from this guide on your own files.
Frequently asked questions
Which format should I use by default?
ZIP if compatibility matters most, since it opens natively on both current Windows and macOS. RAR or 7z if you want stronger compression or specific features and can rely on the recipient having compatible software.
Does compressing a video file make it smaller?
Usually only marginally, since video formats like MP4 are already compressed. Re-encoding the video itself, not archiving it, is what meaningfully reduces its size.
How do I know if my split archive will work for the recipient?
They need every volume in the set in the same folder. Missing a part will cause extraction to fail or stop partway through.
Is a higher compression level always better?
Not necessarily — it takes longer and uses more memory, with diminishing size benefits, especially for files that are already compressed.
Related guides
- What Is File Compression?File compression shrinks data by removing redundancy. How much it shrinks, and whether anything is lost, depends on the method used.
- How to Create a RAR FileOnly RARLAB's own tools can create a genuine RAR archive. Here's how to do it in WinRAR, and what to consider if you'd rather not use it.
- Multi-Part (Split) RAR Files ExplainedA multi-part RAR archive splits one large compressed file into several smaller pieces that must all be present in one folder to extract correctly.
- Password-Protected and Encrypted RAR ArchivesA password-protected RAR archive uses encryption to keep its contents unreadable without the correct password — there is no legitimate shortcut around one you don't know.
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