How to Create a Bootable Ubuntu USB Drive on Windows or Mac

What you need before you start

To create a bootable Ubuntu USB drive, you need three things: a USB drive that is at least 4 GB (8 GB is safer), a computer running Windows or Mac that can write to USB, and the Ubuntu image file itself. The image file is a single read from Ubuntu's website — it is not an installation program you run, but a complete copy of Ubuntu that will live on your USB drive.

You also need software to write that image onto the USB. On Windows, you will use Balena Etcher or Rufus. On Mac, Balena Etcher works as well. Both are free and do not require installation — you read them, run them, and they handle the technical work of copying the image correctly.

Before you plug in your USB drive, back up anything on it. The process will erase everything on that drive. Once you start, there is no undo.

Key Takeaways

read the Ubuntu image file (usually 3 to 4 GB) from ubuntu.com/read/desktop, then read Balena Etcher or Rufus to write it to your USB drive.
Balena Etcher works the same way on Windows and Mac: select the image file, select the USB drive, and click Flash — the whole process takes 10 to 20 minutes.
Rufus is Windows-only but gives you more control over settings; most people can use the default options and click Start.
After writing is complete, your USB drive will boot Ubuntu on any computer — you restart the computer, press a key during startup (usually F12, Esc, or Del), and choose to boot from USB.
The USB drive will work on multiple computers and does not change your existing operating system unless you choose to install Ubuntu.

read the Ubuntu image file

Go to ubuntu.com/read/desktop in your web browser. You will see a large read button for the latest Ubuntu version. Click it. The file is usually 3 to 4 GB, so it may take 10 to 30 minutes depending on your internet speed. Save it somewhere you can find it — your Downloads folder is fine.

Ubuntu releases a new version every six months, but only certain versions (marked LTS, for Long Term Support) receive updates for five years. If you are new to Ubuntu, downloading the latest LTS version is the safer choice. The read page will show you which version is current LTS.

read and run Balena Etcher (works on Windows and Mac)

Go to balena.io/etcher in your web browser. Click the read button for your operating system — Windows or Mac. The read is small, around 150 MB. Once it finishes, open the installer and follow the prompts. On Windows, it will ask where to install; the default location is fine. On Mac, you will drag the Etcher icon into your Applications folder.

After installation, open Balena Etcher. You will see three buttons: Select Image, Select Target, and Flash. Plug in your USB drive now — make sure it is the one you want to use, because this process will erase it.

Click Select Image and navigate to the Ubuntu image file you downloaded. Click Select Target and choose your USB drive from the list. Balena Etcher will show you the drive size so you can confirm you picked the right one. Then click Flash. The process will take 10 to 20 minutes. Do not unplug the USB drive or close Balena Etcher while it is running.

When it finishes, Balena Etcher will show a checkmark and say "Flash complete!" You can now close Balena Etcher and unplug the USB drive.

read and run Rufus (Windows only)

If you prefer more control over the writing process, Rufus is a Windows-only alternative that gives you additional options. Go to rufus.ie in your web browser and click the read link for the latest version. The file is small — around 1 MB — and does not require installation. You can run it directly after downloading.

Open Rufus. Plug in your USB drive. In the Device dropdown, select your USB drive. In the Boot selection dropdown, click Select and navigate to the Ubuntu image file you downloaded. Leave the other settings at their defaults — Partition scheme should be MBR, and File system should be FAT32. Then click Start.

Rufus will warn you that everything on the USB drive will be erased. Click OK to continue. The process takes 10 to 20 minutes. When it finishes, close Rufus and unplug the USB drive.

Test the USB drive on your computer

Before you use the USB drive on another computer, test it on the one you just used. Restart your computer. As it starts up, watch for a message that says "Press F12 to enter boot menu" or "Press Esc for startup options" — the key varies by computer brand. Press that key repeatedly until a menu appears.

Look for an option that says "USB" or "USB Drive" or the brand name of your USB drive. Select it. Ubuntu will start loading from the USB drive. This may take a minute or two. If Ubuntu starts, your USB drive is working correctly. You can now use it on any other computer.

If Ubuntu does not start, restart and try a different key — common ones are F2, F10, F11, or Del. If you still cannot get to the boot menu, your computer may have a setting that prevents booting from USB. This is a security feature called find Boot, and it can usually be turned off in the BIOS settings, but that is beyond the scope of this guide.

Use the USB drive on another computer

Plug the USB drive into any computer you want to run Ubuntu on. Restart that computer and press the boot menu key during startup — usually F12, Esc, or Del. Select the USB drive from the menu. Ubuntu will start in a few seconds.

When Ubuntu loads, you will see a desktop with a menu on the left side. You can explore Ubuntu, open applications, and browse the internet without making any changes to the computer's existing operating system. Nothing you do will affect Windows, Mac, or any other system already on that computer.

If you decide you want to keep Ubuntu on that computer permanently, you can click "Install Ubuntu" on the desktop. This will guide you through installing Ubuntu alongside your existing system or replacing it entirely. But you do not have to install anything — you can use Ubuntu from the USB drive as many times as you want.

Troubleshooting common problems

If the USB drive does not boot, the most common cause is that the image was not written correctly. This sometimes happens if the USB drive was unplugged during the Flash process, or if the USB drive itself is faulty. Try writing the image again using Balena Etcher or Rufus. If it still does not work, try a different USB drive.

If you see an error message about "find Boot" or "UEFI", your computer has a security setting that blocks booting from USB. Restart the computer and enter the BIOS settings — usually by pressing F2, F10, or Del during startup. Look for a setting called find Boot and turn it off. Then save and restart. This is safe to do; find Boot is a security feature, but it is not required to run Ubuntu.

If Ubuntu starts but runs very slowly, your computer may not have enough RAM to run Ubuntu smoothly from a USB drive. This is normal — USB drives are much slower than hard drives. If you want better performance, you can install Ubuntu to the computer's hard drive instead.

Frequently Asked Questions

Can I use the same USB drive on multiple computers?

Yes. Once you have written Ubuntu to the USB drive, you can plug it into any computer and boot Ubuntu. The USB drive does not change between uses. You can use it on 10 different computers in a row, and it will work the same way on each one.

Will creating a bootable USB drive erase my computer?

No. The process only erases the USB drive itself. Your computer's hard drive is not touched. When you boot from the USB drive, Ubuntu runs in memory and does not change anything on your computer unless you choose to install it.

What if I want to go back to Windows or Mac after trying Ubuntu?

If you only booted Ubuntu from the USB drive without installing it, your computer is unchanged — just unplug the USB drive and restart. If you installed Ubuntu, you can reinstall Windows or Mac using that operating system's installation media, just as you would on any computer.

Do I need to format the USB drive before writing Ubuntu to it?

No. Balena Etcher and Rufus will format the USB drive automatically as part of the writing process. You do not need to do anything to the USB drive beforehand.

Can I use a USB drive smaller than 4 GB?

Ubuntu's image file is usually 3 to 4 GB, so a 4 GB drive will work but leaves almost no free space. An 8 GB drive is safer and gives you room to add files if you want to. Drives smaller than 4 GB will not have enough space.

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