What is the difference between a bit and a byte?

A bit (binary digit) is the smallest unit of data in computing, representing a 0 or a 1. A byte is a group of 8 bits. Bytes are typically used to measure file sizes (e.g., kilobytes, megabytes), while bits are often used to measure network speed (e.g., megabits per second).

Why is my internet speed in Megabits (Mbps) but my downloads are in Megabytes (MB/s)?

This is a common point of confusion. Internet Service Providers (ISPs) advertise speeds in megabits per second (Mbps). Since there are 8 bits in a byte, to find your theoretical maximum download speed in megabytes per second (MB/s), you divide your internet speed by 8. For example, a 100 Mbps connection has a maximum download speed of 12.5 MB/s.

Is a Kilobyte 1000 or 1024 bytes?

Both are used. In the decimal system (base-10), used for marketing and simplicity, 1 Kilobyte (KB) = 1000 bytes. In the binary system (base-2), used by operating systems, 1 Kibibyte (KiB) = 1024 bytes. This calculator allows you to choose which system to use for your conversions.

Data Size & Bandwidth Calculator

Estimated Download Time

How Does This Work?

This dual-purpose calculator helps you understand digital data sizes and network speeds.

Data Size Converter: It converts between different data units (like bits, bytes, kilobytes, and gigabytes). It first converts your input value into a base unit (bits), and then uses that to calculate the equivalent in all other units. You can choose between the decimal system (base 1000, used in marketing) and the binary system (base 1024, used by operating systems).
Download Time Calculator: It estimates how long a file will take to download over a network connection. It calculates this using the formula: Time = File Size / Bandwidth. The calculator first converts both the file size and the bandwidth into a common unit (bits) to ensure the calculation is accurate.

The Surprising History of the "Bit"

The "bit," the fundamental unit of all digital information, was not conceived in the age of computers, but in the age of information theory. The term was coined by the brilliant mathematician and engineer Claude Shannon in his groundbreaking 1948 paper, "A Mathematical Theory of Communication."

Shannon, working at Bell Labs, was trying to find the most efficient way to send information over noisy channels like telephone lines. He needed a basic unit to measure information. He adopted the term "bit," a contraction of "binary digit," which had been suggested by his colleague John W. Tukey. Shannon showed that all information—text, images, sound—could be broken down into a series of these simple yes/no, on/off choices (0s and 1s). This simple concept laid the mathematical foundation for the entire digital revolution that followed.

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Frequently Asked Questions (FAQ)

What is the difference between MB and Mb?

The case of the 'b' is very important. A capital 'B' stands for **Byte**, while a lowercase 'b' stands for **bit**. Since there are 8 bits in a byte, 1 MB (Megabyte) is 8 times larger than 1 Mb (Megabit).

Why is my download speed slower than what my ISP advertises?

Advertised speeds are theoretical maximums ("up to"). Real-world speed is affected by many factors, including network congestion, the speed of the server you're downloading from, Wi-Fi signal strength, and overhead from network protocols. Our download time calculator provides an estimate based on your stated bandwidth.

Should I use the decimal (1000) or binary (1024) system?

It depends on the context. Hard drive manufacturers and internet providers typically use the decimal system (1 KB = 1000 bytes). However, your computer's operating system (like Windows or macOS) uses the binary system (1 KiB = 1024 bytes) to report file sizes. This discrepancy is why a 1 TB hard drive often shows up as only about 931 GB on your computer.

Data Size Converter

Equivalent Sizes:

Download Time Calculator