Bits for links, bytes for storage
Network equipment moves one bit at a time, so link speeds are quoted in bits per second: 100 Mbps Ethernet, 1 Gbps fibre, 300 Mbps Wi-Fi. Files are stored as bytes, and every storage interface counts the same way. Since 1 byte = 8 bits, a speed in MB/s is always exactly one eighth of the same speed in Mbps — no rounding, no vendor tricks.
Conversion table
- 10 Mbps = 1.25 MB/s — entry-level broadband, one 1080p stream
- 50 Mbps = 6.25 MB/s — comfortable for streaming and game downloads
- 100 Mbps = 12.5 MB/s — the common sweet spot; a 10 GB update in 13 minutes
- 300 Mbps = 37.5 MB/s — several 4K streams plus downloads
- 1 Gbps = 125 MB/s — a 50 GB game in about 7 minutes at line rate
Overhead is the second discount
Line rate counts every bit on the wire, including packet headers, acknowledgements and retransmissions. TCP/IP and Ethernet framing cost around 5%, TLS and application protocols a little more, and Wi-Fi management frames can double that. Practical throughput on wired connections is 90–95% of the plan; at Wi-Fi range it is often 50–70%. A 100 Mbps plan measuring 95 Mbps in a speed test and 11 MB/s in a download manager is performing exactly as expected.
Using the numbers before you buy
Multiply the file throughput you need by 8 to find the plan speed. Downloading a 60 GB game overnight (8 hours) needs 60,000 MB ÷ 28,800 s = 2 MB/s sustained, about 17 Mbps — so a 50 Mbps plan leaves plenty of margin. Uploads follow the same maths at a fraction of the speed: 10 Mbps upload moves 1 GB in 13 minutes.