If you feel confused by how much memory and storage space your computer actually has or you’re baffled by KB, MB and GBs, it’s not surprising. It’s not as straightforward as you’d think. There are two different ways of expressing the storage space and memory of your computer. This is a simplified explanation of what’s going on, but if you don’t want the math behind the answer, you can skip straight to the end.

### Understanding Binary vs. Decimal Numbers

First, a brief math lesson. We do our day-to-day math in a decimal system. The decimal system has ten digits (0-9) that we use to express all of our numbers. Because computers are made from electrical components that are either on or off, they use a binary system for storage and memory. The binary system has only two digits (0 & 1) that are used to express numerical values. For example, to get to the decimal number 4 in binary you would count like this: 00,01,10,11. If you want to go higher than that, you need more digits.### What’s All This About Bits and Bytes?

*Bit*

A bit is the smallest increment of storage on a computer. Imagine each bit is like a light bulb. Each one is either on or off, so it can have one of two values (either 0 or 1).

*Byte*

A byte is a string of 8 bits (eight light bulbs in a row). A byte is basically the smallest unit of data that can be processed on your family computer. As such, storage measurements are always done in bytes rather than bits. The largest decimal value that can be represented by a byte is 2^{8} (2 x 2 x 2 x 2 x 2 x 2 x2 x2) or 256. For more information on binary numbers, including how to convert them to decimal, please see the resource area below.

*Kilobyte (KB)*

A kilobyte in binary is 1024 bytes(2^{10}), but it also used to refer to 1000 bytes (the decimal interpretation). This is where things start to get really confusing! You can see that a binary KB is slightly bigger than a decimal KB.

*Megabyte (MB)*

A megabyte in binary is 1,048,576 (2^{20}) bytes. In decimal it’s 1,000,000 bytes (10^{6}).

*Gigabyte (GB)*

A gigabyte is either 2^{30} (1073741824) bytes or 10^{9} (1 billion) bytes. By now the difference between the binary version and the decimal version is quite significant.

### So How Much Memory/Storage Do I Have?

The biggest reason that people get confused is that sometimes manufacturers provide information in decimal and sometimes they provide it in binary. Hard drives, flash drives and other storage devices are usually labeled in decimal. Memory (such as RAM) and software typically provide binary values. Since 1GB in binary is bigger than 1GB in decimal, the rest of us are often confused about how much space we’re actually getting/using. And worse, your computer may say it has an 80GB hard drive, but your operating system (which reports in binary!) will tell you that it’s actually a less (by ~7-8 GB).

The easiest solution to this issue is to just ignore it as much as possible. When you purchase a storage device, remember that you’re getting slightly less than you think and plan accordingly. Basically, if you have 100 GB in files to store or software to install, you’ll need a hard drive with at least 110 GB of space.