Expert Eye

How do you turn an Internal Hard Drive into an External Drive?


This article was updated in May 2021

Here’s an Ebuyer quick guide on how to turn an Internal Hard Drive to an External Drive.

It seems like a pretty logical step. You might have an old internal hard drive you don’t want to use lying around. Can it be put to good use and converted it into an external drive?

Well the answer is yes… It can. And it’s easier than you thought. You just need a few extra parts and bit of forward planning.

The internal workings of a Hard Drive (Shutterstock)

Browse Ebuyer’s range of internal Hard Drives here

Why do I need an external hard drive?

It’s always a great idea to have an external drive as a backup just in case your desktop PC does ever fail. If you’ve ever upgraded your computer or simply have old hard drives lying around it’s possible to convert the unit into an external hard drive.

As you can imagine by looking at the Internal Hard Drive, it lacks connections and protection for use in the big bad world. The SATA or IDE connections it comes with are only really useful if it’s installed inside a computer. So you need to add a way for it communicate with other bits of tech. You need a USB (the most common type of connection for external hard drives and most compuyer peripherals) or a Firewire bridge.

For this you need an Enclosure [or ‘Caddy’ as they are known]. These cases are both converter, protector and holder for the internal hard drive.


Enclosures are boxes that the internal drives sit in. They come compatible with two interfaces: IDE and SATA. Of the two, SATA hard drives are much more common now than IDE and are likely to be the one you need. Always check first, as the connections differ.


Depending where your internal hard drive came from originally, the size of the drive will vary. 3.5” (3.5 inch) hard drives are used in desktop computers, with 2.5” (2.5 inch) drives found usually in notebooks. 3.5” drives are usually bigger, faster, and cheaper to buy – but because a 2.5 inch device is naturally smaller it’s more portable.


Most external hard drives connect to your computer through USB (3.0, 2.0 and 1.1) or FireWire. Choose your connection type based on what your priority use will be. Mac users focusing on video may consider Firewire as the computer is more suited to this connection. Your standard office or home user will find USB more useful.

Number of Bays

This option is useful for those wanting to backup large files or partition secure software. Some Enclosures offer different numbers of bays (essentially, how many internal drives it can hold in one box). A dual bay enclosure would hold two hard drives- double the storage of a standard enclosure.

Shop for Hard Drive enclosures at Ebuyer, here


The enclosures tend to vary in price depending on what you need it for. A simple hard drive enclosure at approximately £10 will have one simple connection and will ideally be suited to those wanting to use it as a straight back up.

The £10 – 40 range is where you will see a larger array of connection types, material qualities and speeds. These enclosures are aimed at those with more information to move: photographers, video editors and gamers.

£40+ enclosures tend to be the top speed specification. These are best used with high speed Hard Drives. Many also have networking capabilities, meaning your hard drive is turned into a basic NAS drive – files shared via Wi-Fi direct to a TV or tablet.

laptop and external hard drive
An external Hard Drive connected to a laptop (Shutterstock)

How do you do it?

The process of housing the hard drive is very simple.

Open the enclosure along the designated line. Some unscrew, others clip. Try and do it on a clean static free surface, to avoid contaminating the drive.

Place the internal hard drive inside, if you have the right size it should be obvious how it lines up.

Connect all the necessary cables. Usually, you’ll have a power source, SATA connection and holding clips…

If it’s a 3.5” holder it’s likely you will need external power (included). A 2.5” will run off the USB connection.

Then plug it into your PC and register it to your computer.

That’s it! Now you can use your old hard drive like any new external device!

If the idea of repurposing in this way, and fitting in a new enclosure, doesn’t appeal you can always check out the range of external hard drives at Ebuyer. You can also read more on Hard Drives at the Ebuyer blog and in-depth Knowledge Hub.

Browse Ebuyer’s range of external Hard Drives here

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