A bit is the smallest unit of storage and stores just a 0 or a 1. Internet speed is measured in bits-per-second and is used to show how much data can be moved from a server through the Internet to your computer every second. Internet speed is expressed as “bits per seconds” or “megabits per second (Mbps).” One megabit equals one million bits. Megabit is written with an uppercase "M" and a lowercase "b", as in Mb. For example, with a download speed of 20 Mbps, your Internet modem is capable of being more than three times faster than a 6 Mbps service plan.
A byte is a grouping of eight bits. For example, the eight-bit string of code 10010101 is exactly one byte. Bytes are often used when referring to the size of an electronic file, such as music, photos and videos. One megabyte equals one million bytes. Megabyte is written with an uppercase "M" and an uppercase "B", as in MB. So a photo might be 1MB, a song 5MB and a video 700MB.