This depends on your computer’s processor, the HDD type, and, of course, its size – the larger the capacity, the longer it is to wipe. Typically, it takes roughly 1-3 hours for DBAN to wipe a 1TB hard drive. However, if your computer is really old and its processor is slow, it might take longer than this. If you need to quickly delete the data and ensure that it’s unrecoverable, you can also use a physical method of hard drive destruction.