Your internet plan says 100 and your download manager says 12.5. Both are right, because they use different units.
Side by side
| Megabit (Mb) | Megabyte (MB) | |
|---|---|---|
| Equals | 1,000,000 bits | 8,000,000 bits |
| Usually measures | Connection speed (Mbps) | File size and storage |
| Written with | Lowercase b | Uppercase B |
| Convert to the other | Divide by 8 | Multiply by 8 |
Worked examples
- 100 Mbps is 12.5 MB per second at best.
- A 500 MB file on a 50 Mbps line takes 4,000 ÷ 50 = 80 seconds.
- A 2 GB file on 100 Mbps takes 160 seconds.
Try your own numbers in the Bandwidth Calculator.
Real-world speeds
You will almost never reach the advertised figure, because of Wi-Fi, server limits and shared connections. Treat it as a ceiling. For a full walk-through read how to calculate file download time, and see the bit and byte glossary entry.