If we ignore the scandal specifications and the mileage figures that different telephone and computer manufacturers usually accustom us to, **the bit is the most basic unit of information** if we talk about digital devices. When speaking of a binary system (or and 1), a bit is the unit that contains two possible combinations of numbers, and a byte is the set of 8 bits whose figure can hold up to 256 possible combinations of 0 and 1 (that is, 2 raised to 8).

Starting from this principle, **manufacturers play to offer figures that do not correspond to the real capacity** of the product in question, be it a hard disk, a memory card or a fiber optic tariff.

## 1 TB is not equal to 1,000 GB, but to 931 GB

The surprise to see that our brand new 1 TB capacity hard drive does not have 1,000 GB, but 931 GB, is a feeling that most users have experienced at some time in our lives. **Where is the remaining 69 GB? **Nowhere.

Despite the fact that the basic computing unit (bit) is a binary system of 0 and 1, the units used when dealing with more well-known figures **are based on a decimal system** . And it is that while the binary units refer to the bit (Mb, Gb, Tb ...), the decimal units comprise the byte (MB, GB, TB ...), at least commercially.

The relationship, therefore, leaves us a proportion similar to the following:

- 1 byte equals 8 bits
- 1 kilobyte is equal to 8 kilobits (or 8,000 bits)
- 1 megabyte equals 8 megabits (or 8 * 10 ^ 6 bits)
- 1 gibabyte is equal to 8 gigabits (or 8 * 10 ^ 9 bits)
- 1 terabyte is equal to 8 terabits (or 8 * 10 ^ 12 bits)

To this we must add that a kilobyte does not correspond to 1,000 bytes, **but to 1024 bytes, having a base of 2** . Remember that the system it represents is binary, therefore, it has to make use of multiples of 2.

- 1 kilobyte equals 1,024 bytes
- 945 kilobytes equals 967,680 bytes
- 100 gigabytes equals 102,400 megabytes
- 3 terabytes equals 3,072 gigabytes

## How to calculate the real capacity of a hard disk or memory

When calculating the capacity of a hard disk or memory card, it is necessary to take into account aspects such as **the space occupied by the firmware of the hard disk itself or the operating system** , in addition to the respective programs in case of having a disk pre-installed.

Starting from this premise, the formula to calculate the real capacity of a hard disk is solved based on the following variables:

- Actual Disk Capacity = Manufacturer's Indicated Capacity x 0.9313

If we do the test with a 1 TB hard drive, the formula is as follows:

- 1TB x 0.9313 = 0.9313TB (about 930GB)

We leave you below with a roadmap with the most common capacities converted to their real capacity:

- A 250GB hard drive has an actual 232GB
- A 320GB hard drive has an actual 298GB
- A 500 GB hard drive has an actual 465 GB
- A 1 TB GB hard drive has actual 931 GB
- A 1.5 TB hard drive has an actual 1396 GB
- A 2 TB hard drive has an actual 1862 GB
- A 3 TB hard drive has an actual 2793 GB

## The other great forgotten: Internet speed

Beyond the physical capacities of hard drives and memory cards, if there is a great forgotten when making this type of conversions it is the speed of the Internet.

Telephone companies often mention fiber and mobile speeds of 100 Mb, 500 Mb and even 600 Mb. **The unit used this time is the bit** , which can lead to confusion among users with little computer literacy.

Thus, a download and upload speed of 600 megabits (Mbps) will give us a real speed of 75 megabits per second (MB / s). The formula used in this case is the following:

- Real contracted speed = Amount in megabits per second indicated by the operator x 0.125

If we have, for example, a speed of 200 Mbps, the real speed would be calculated as follows:

- 200 Mbps x 0.125 = 25 MB / s

Below you can know the conversion to MB / s with the most common speeds:

- A 30 Mbps rate offers a maximum download and upload speed of 3.75 MB / s actual
- A 50 Mbps rate offers a maximum download and upload speed of 6.25 MB / s actual
- A rate of 100 Mbps offers a maximum download and upload speed of 12.5 MB / s actual
- A 200 Mbps rate offers a maximum upload and download speed of 25 MB / s actual
- A rate of 300 Mbps offers a maximum download and upload speed of 37.5 MB / s real
- A rate of 500 Mbps offers a maximum download and upload speed of 62.5 MB / s actual
- A 600 Mbps rate offers a maximum download and upload speed of 75 MB / s actual
- A 1 Gbps rate offers a maximum download and upload speed of 125 MB / s actual