How to get the real capacity of your hard drive

[paularoid]

This comes from one of the latest issues of PC Mechanic.

How to Get the Real Capacity of Your Hard Drive

Manufacturers calculate drive capacity slightly differently than how computers actually see usable storage space. Manufacturers count drive capacity using the decimal system, while computers count drive capacity using the binary system. So, when you wish to convert to one system of measurement to another, there are discrepancies, much like the way there are discrepancies when converting between the Celsius and Fahrenheit temperature scales.

So, to calculate the actual drive capacity, take the manufacturer's advertised capacity and divide it by 1.024 three times. For example, if you take an 80GB drive capacity and divide it by 1.024 three times, you will get 74.5GB of actual storage space.

For reference, here's a list of common drive capacities matched with their actual data capacities (rounded to the nearest hundredths place):

10 GB = 9.31 GB
20 GB = 18.63 GB
30 GB = 27.94 GB
36 GB = 33.53 GB
40 GB = 37.25 GB
60 GB = 55.88 GB
74 GB = 68.91 GB
80 GB = 74.51 GB
100 GB = 93.13 GB
120 GB = 111.76 GB
160 GB = 149.01 GB
180 GB = 167.64 GB
200 GB = 186.26 GB
250 GB = 232.83 GB
300 GB = 279.40 GB
320 GB = 298.02 GB
400 GB = 390.62 GB
.

[DaveM]

My 250 gig drive is partitioned with the partition labeled as Drive "D" and containing installable copies of the OS and all of the original crap that came with the machine. While it did indeed allow me to make backup disks should a complete restore ever become necessary, meanwhile I presume the partition leaves me with FAR less than 250 GB of available space.

As I also have a 120 GIG external HD, however, I really don't think I'm likely to run out of space.

[TechGirl]

Dave,
You can back up all that stuff on an external drive and then delete that second partition if you want more hard drive space. Not sure how much space it is taking up, but with external storage being so cheap, it might not be an issue either way.

It would mean having a way to boot up and work on your PC in case something went wrong. If you feel comfortable with that, I would kill the second partition, but if you store mostly picture and files, I would just buy more external drives since you can attach them to any machine you own long term.