Data rate units and their equivalents
| Unit | Symbol | In Mbit/s |
|---|---|---|
| Gigabit per second | Gbit/s | 1,000 Mbit/s |
| Megabit per second | Mbit/s | 1 Mbit/sbase unit |
| Kilobit per second | kbit/s | 0.001 Mbit/s |
| Bit per second | bit/s | 0.000001 Mbit/s |
| Gigabyte per second | GB/s | 8,000 Mbit/s |
| Megabyte per second | MB/s | 8 Mbit/s |
| Kilobyte per second | kB/s | 0.008 Mbit/s |
| Byte per second | B/s | 0.000008 Mbit/s |
Frequently asked questions
Why is my 1 Gbit/s fibre only 125 MB/s?
Because the line is counted in bits and the file in bytes, and a byte is eight bits. 1 Gbit/s is 1,000 Mbit/s, which is 125 megabytes per second. Nothing is lost: the two numbers measure the same flow in two units.
Why do providers sell in megabits?
Because the number is eight times larger, and because the bit is the historical unit of transmission: a line carries pulses, not files. Both reasons hold at once, and only the first is a marketing one.
How long does a 5 GB file take on a 100 Mbit/s line?
Just under seven minutes at full speed. 5 GB is 40 gigabits, that is 40,000 megabits, and at 100 megabits per second that comes to 400 seconds. Real transfers are slower: the protocol overhead takes a few per cent.
Is Mbps the same as MB/s?
No, and the capital letter is the whole difference. Mbps means megabits per second, MB/s means megabytes per second, and there is a factor of eight between them. Written Mbit/s, the symbol removes the ambiguity that Mbps keeps.
Do binary prefixes apply to data rates?
No. A megabit per second is exactly one million bits per second, in decimal, and the mebibit per second has no ordinary use. The kibi and mebi trap belongs to storage, where a 1 TB drive reads 931 GB; transmission never had it.