Mbps vs MB/s: why downloads look 8 times slower than your plan
You pay for 100 Mbps, yet your download manager shows about 12. Nothing is wrong. Two different units are being used, and they differ by a factor of eight.
Bits and bytes
Internet plans are measured in megabits per second, written Mbps, with a small b. File sizes and download managers use megabytes per second, written MB/s, with a capital B. One byte is eight bits, so to convert Mbps to MB/s, divide by 8.
Quick conversion table
| Plan speed | Best-case file speed |
|---|---|
| 50 Mbps | 6.25 MB/s |
| 100 Mbps | 12.5 MB/s |
| 300 Mbps | 37.5 MB/s |
| 500 Mbps | 62.5 MB/s |
| 1000 Mbps (1 Gbps) | 125 MB/s |
How long will a download take?
Multiply the file size in megabytes by 8 to get megabits, then divide by your speed in Mbps. A 1 GB file (about 1000 MB) at 100 Mbps takes about 80 seconds. A 10 GB game at 500 Mbps takes about 160 seconds.
Why real downloads are a bit slower still
Protocol overhead, the speed of the server you download from, Wi-Fi quality and other devices on your network all reduce the real figure. Getting 90 to 95 percent of the theoretical value on a good wired line is normal.
Check your real speed
Run a speed test and read the result in Mbps, the same unit as your plan, so you compare like with like.
Frequently asked questions
Is Mbps the same as MB/s?
No. One MB/s equals 8 Mbps.
How many MB/s is 100 Mbps?
About 12.5 MB/s in the best case.
Why do providers use Mbps?
It is the standard unit for network speed, and it gives larger numbers than MB/s.