100Mbits

100 Mbits, abbreviated as 100 Mbps, is a data transfer rate defined as 100 million bits per second. In contrast to megabytes per second (MB/s), which measure data in bytes, 100 Mbps corresponds to about 12.5 megabytes per second of raw data transfer. Real-world throughput is typically lower due to protocol overhead and network conditions.

In networking, 100 Mbps historically signified Fast Ethernet. The most common physical implementations are 100BASE-TX, which runs over copper twisted-pair cables such as Cat5e or Cat6, and 100BASE-FX, which uses fiber. These standards sit between older 10 Mbps Ethernet and higher-speed technologies like 1 Gbps (1000 Mbps) and beyond. While many networks have upgraded, 100 Mbps remains in use on legacy installations and some consumer devices.

In home and small business contexts, 100 Mbps networks provide moderate performance for day-to-day tasks, including web browsing, video streaming, and file transfers. In internet service terms, providers may market plans as “up to 100 Mbps,” with actual speeds affected by factors such as line quality, network congestion, router capabilities, and wireless interference. When measured end-to-end, the effective throughput is often lower than the nominal 100 Mbps, particularly on shared or wireless links.

Conversion and comparison are common sources of confusion. A 100 Mbps link delivers 100 million bits each second, whereas a file size is usually expressed in megabytes or gigabytes. Understanding the distinction between bits and bytes helps explain why reported speeds and usable data transfer can differ by a factor of eight.