Hard Drive Storage Capacity Wrong?

Have you ever noticed that maybe you bought a computer that advertised that it said "250 gigabytes" of storage and when you got home and booted it up for the first time to find out that windows is reporting it less than that? No, you have not been ripped off. The idea happened some year in the distant past when the idea of kilobyte arrived. Kilo in the metric system means 1,000. Unfortunately, in the computer world kilobyte means 1,024. First lets get comfortable with understanding the system. Below is a chart to review for the moment.  Unit Name  Abreviation  Binary Power  Binary Value (represented in Decimal)  Decimal Power  Decimal (Equivalent)  Kilobyte KB   210  1,024  103  1,000  Megabyte MB  220  1,048,576  106  1,000,000  Gigabyte GB  230  1,073,741,824  109  1,000,000,000  Terabyte TB  240  1,099,511,627,776  1012  1,000,000,000,000 As you can see above there is a difference between the decimal binary value and the decimal only equivalent.  Hard drive manufacturers use decimal only.  They believe in the true metric system.  Meanwhile there is a confusion between computer lingo and the real thing.  Let me show you an example of what I mean.  Below is a graphic out of windows xp pro.  (This is found by going to your my computer, and right clicking on the local disk drive icon, go to properties.) So, as you can see in this example the actual drive capacity is 250,048,479,232 bytes or advertised 250 gigabytes.  The real reported storage space is 232 gigabytes.  You could arrive at this number by dividing 250,048,479,232 by 1,073,741,824 to get 232,875,793,457,031.25 or rounded 232GB +-. Hopefully this helps you understand the reasoning behind why your computer is telling you have less space than you thought you should have. Return to Education Main Page