Bytes to GB Calculator

A tool to convert from bytes to gigabytes will take the original number of bytes and turn it into gigabytes. This is the unit that actually measures data on a hard drive, smartphone or downloaded content. As you enter a value and select a unit, all other units will be instantly converted for you.

There is one almost unique very fine difference that confuses most people: a gigabyte (GB) can mean two different sizes.

Marketing experts and storage manufacturers use the decimal system, so a GB they quote is exactly 1,000,000,000 bytes. Operating systems however use the binary system, so a GB quoted by an operating system is technically a GiB which is 1,073,741,824 bytes. This tool shows both results side-by-side so it's always clear what size is being shown.

To convert bytes to gigabytes, do the following:

If it is a decimal gigabyte, the unit on the packaging, divide the number of bytes by one billion.

The formula for calculating a decimal gigabyte is: $\text{GB} = \dfrac{\text{bytes}}{1{,}000{,}000{,}000}$.

When we talk about binary gigabytes (GiB), the unit that a computer displays, we divide by 1,073,741,824. This number is the 30th power of 2.

The formula for calculating binary GiB is: $\text{GiB} = \dfrac{\text{bytes}}{1{,}073{,}741{,}824} = \dfrac{\text{bytes}}{2^{30}}$.

Let's take a concrete example. Let's say that a file has a size of 5,000,000,000 bytes.

Dividing by a billion gives you 5 GB in the decimal system. Dividing by 1,073,741,824 gives you about 4.66 GiB, which is what will be shown in a file manager. So there are two different displays for the same file.

Conversion table of Byte to GB:

This table shows the number of bytes for each power of ten. Notice that the difference between the decimal and binary columns grows gradually as the numbers get larger.

The difference between GB and GiB and why your hard drive capacity looks smaller:

Sometimes a computer will show about 465GB of usable capacity even though you bought a 500GB drive. Nothing is lost and the drive isn't broken; it's just that both units use different numbering systems.

Manufacturers list the capacity of a hard drive in decimal gigabytes, so 500GB means 500 billion bytes. The operating system divides that same number of bytes by 1,073,741,824 and gets about 465. Although it is technically GiB, it displays as GB, and this inconsistency in labeling is the source of confusion.

As a rule of thumb, one binary gigabyte is about 7 percentage points larger than one decimal gigabyte. The difference increases with increasing units; at the terabyte level it reaches about 10 percentage points.

The levels of data units:

Each unit here is based on bytes. Decimal units are multiplied by 1000 each time they increase, while binary units are multiplied by 1024. A bit is smaller than a byte and consists of eight bits.

What is a byte?

A byte consists of a group of eight bits, where each bit represents either a 0 or a 1. Eight bits can produce 256 different patterns, which is exactly the number needed to represent a single text character. Thus, the byte has become the natural base unit for data storage.

The term was coined by Werner Buchholz at IBM in 1956. He chose the spelling with a "y" to avoid confusion with the concept of a bit. Storage capacity is measured in kilobytes, megabytes, gigabytes and higher units, all multiples of bytes.

What is a GB?

In the decimal system a GB is equal to one billion bytes, which is the capacity advertised by hard drive manufacturers. In the binary system the corresponding unit is GiB, which equals 1,073,741,824 bytes.

A gigabyte can store a large amount of data, such as an hour of standard video quality, hundreds of songs or thousands of photos. Since cell phone plans, memory cards and app downloads are almost always listed in GBs, it is helpful to convert the original number of bytes into GBs for better understanding.

Where are these conversions used?

They are used when you read the file size in bytes that an app shows and want to display it in GBs to check if a backup will fit on a hard drive, or compare a smartphone with 128GB of storage to one with 256GB.

A computer with 8GB of RAM has 8 billion bytes and the software reports about 7.45GiB. A single layer Blu-ray disc can hold 25GB, a dual-layer disc holds 50GB so approximately 46.6GiB. Once you understand these two numbers you will not question the difference often.

A short history of GiB

For decades "kilo", "mega" and "giga" were used to mean both 1000 and 1024, and people had to live with the ambiguity. When hard disk capacities reached the GB range, the difference became noticeable.

In 1998 the International Electrotechnical Commission solved this problem by naming binary units: kibibyte, mebibyte, gibibyte, etc. The decimal prefixes "kilo", "mega" and "giga" were preserved to represent powers of 1000 just as in other scientific fields.