How to Keep Wikipedia Offline on a USB Drive

When the internet is down, so is almost every reference most of us use. An offline copy of Wikipedia solves a surprising amount of that: how a sump pump works, what a medication is for, how to splint a finger, how to identify a tree. It costs little more than a USB drive and an evening of downloading.

This guide covers the files, the drive, the steps and the upkeep. Everything here can be done with free software.

What you need

• Kiwix, a free, open-source reader for offline websites. It runs on Windows, macOS, Linux, Android and iOS.
• A ZIM file, the compressed archive format Kiwix reads. One file holds an entire site, including its search index.
• A USB drive with enough space, formatted so it can hold very large files.
• A fast, unmetered internet connection for the download. The large files take hours.

How big is Wikipedia?

Kiwix publishes several English editions. These sizes come from the Kiwix download index in 2026, and they grow by several gigabytes a year.

A note on units: drive makers count in gigabytes (GB) and some download listings use gibibytes (GiB), which are about 7% larger. A drive sold as 128 GB holds less than its label suggests once formatted, so the images edition is a tight fit on it. For the full edition plus other material, 256 GB is the practical size.

Step by step

1. Choose the drive. Pick 256 GB if you want the images edition and other references, or 64 GB or more for text only. A drive with both USB-C and USB-A plugs works with phones and older computers.
2. Format it as exFAT. The older FAT32 format cannot hold any single file larger than 4 GB, and the Wikipedia file is far larger. exFAT is readable by Windows, macOS, Linux and most recent phones. Formatting erases the drive.
3. Download Kiwix for each device you might use, and save the installers on the drive as well. In an outage you may be using a different computer from the one you set up.
4. Test with the small file first. Download the top 100 sampler, open it in Kiwix and confirm that search works.
5. Download the full ZIM file from the Kiwix library. For a file this large, a torrent client or a download manager that can resume is more reliable than a browser.
6. Copy the file to the drive and open it in Kiwix from there. The first opening can take a moment.
7. Test it properly offline. Turn on airplane mode, plug the drive into your phone and your laptop, and look something up on each.
8. Label the drive with the contents and the build date, and write that date somewhere you will see it in a year.

What else is worth storing

Wikipedia is broad, but it is an encyclopedia and not a manual. A few other collections fill the gaps, and several are available as ZIM files from the same library. Check the current size of each in the listing before you plan your drive.

• A medical reference. There are offline medical encyclopedias built from Wikipedia's health articles. They are reference material and do not replace a first-aid course or professional care.
• Repair guides. Step-by-step guides for appliances, electronics, bicycles and vehicles.
• Books. Public-domain collections include cookery, gardening, woodcraft and a great deal of fiction, which matters more than you might expect on day four without power.
• How-to and textbook wikis. Wikibooks and similar projects are closer to instructions than encyclopedia articles are.
• Offline maps. Several free map apps let you download whole provinces from OpenStreetMap data. OpenStreetMap asks for attribution if you redistribute it.
• Your own documents. Scans of ID, insurance policies, prescriptions, appliance manuals and a contact list. Encrypt anything personal.

Paper still earns its place. A printed manual works with no battery at all, which is why we suggest keeping at least one printed reference beside any digital library. Our long-term preparedness guide goes into this further.

Is it legal to copy Wikipedia?

Yes. Wikipedia's text is published under the Creative Commons Attribution-ShareAlike 4.0 licence, which allows anyone to copy and redistribute it, including commercially, as long as the authors are credited, the licence is stated, and any modified version carries the same licence. Kiwix files keep the attribution on each article page. Images are licensed individually, and the Wikipedia name and logo are trademarks that the licence does not cover.

Drive choice and upkeep

The points below are our own judgement. There is no official standard for a household offline library.

• Buy a known brand from a reliable seller. Counterfeit drives that report a false capacity exist, and a very large file is exactly what exposes them. Copying the full file and opening it is a good test.
• Keep two copies. A second drive, or a copy on a laptop, costs little compared with redoing the download.
• Plug it in once a year. Open a few articles to confirm the drive still reads. Flash storage is not meant to sit untouched for decades.
• Refresh the content every year or two. Medical and technical articles change. Replace the file when you do your annual kit check.
• Store it cool and dry, in a labelled case, with the cable or adapter your phone needs.
• Plan for power. A library is only as useful as the device that reads it. A phone uses very little energy for reading, so a small power bank or power station goes a long way. See what size power station you need.

If you would rather not spend the evening downloading and testing, a ready-made drive is an option. Ours is described on the offline knowledge page. ICEKIT is not affiliated with or endorsed by the Wikimedia Foundation or Kiwix.

Sharing the library with a household

One drive serves one device at a time. For a family, the simplest approach is to copy a smaller edition onto each phone in advance. Kiwix also offers server software that lets one computer share a library over a local Wi-Fi network, so nearby phones can read it in a browser without installing anything. A small single-board computer can do this job on very little power.

Whichever route you choose, the test is the same. Switch off your router for an hour on an ordinary evening and try to answer three real questions from the library. If that works, it will work when you need it.

Frequently asked questions

Sources

• Kiwix download index: Wikipedia ZIM files
• Kiwix: frequently asked questions
• Wikipedia: reusing Wikipedia content
• Creative Commons: Wikipedia moves to CC 4.0 licences
• OpenStreetMap Foundation: licence and legal FAQ

General information only. Follow instructions from local emergency officials, and call 911 in a life-threatening emergency.