Internet plans are sold in megabits per second but downloads show megabytes per second, which makes a 100 Mbps connection look eight times slower than advertised. This converter handles bits and bytes at every scale, including the decimal (megabyte) and binary (mebibyte) versions, so you can see what a plan really delivers.
How to use it
- Enter a speed.
- Choose the unit it's in, for example Mbit/s.
- Choose the unit you want, such as MB/s.
- Read the result and the full table.
When it helps
- Working out how fast a 100 Mbps plan can actually download a file.
- Comparing broadband offers quoted in different units.
- Estimating how long a backup or upload will take.
- Network and hosting planning.
Good to know
- Divide megabits by eight to get megabytes: 100 Mbit/s is 12.5 MB/s.
- Real downloads run a bit under the maximum because of protocol overhead and Wi-Fi conditions.
- A mebibyte is 1,048,576 bytes while a megabyte is 1,000,000, a difference that shows up in large transfers.
Bits, bytes and prefixes
A byte is eight bits, so a rate in bytes per second is an eighth of the same rate in bits. Internet providers advertise in bits because the numbers are bigger, and operating systems show bytes. A 100 megabit connection therefore downloads at about 12.5 megabytes per second at best.
The prefixes add another wrinkle. Kilo, mega and giga in networking mean powers of 1,000, while kibi, mebi and gibi mean powers of 1,024. A mebibyte is 1,048,576 bytes, about 4.9 percent bigger than a megabyte.
Worked example: how long will a download take?
A game is 50 gigabytes and your connection is 200 Mbit/s. Enter 200 with Mbit/s selected and read the MB/s line: 25. Fifty gigabytes is 50,000 megabytes, so at 25 MB/s it takes 2,000 seconds, a little over 33 minutes.
In practice, expect somewhat longer. Protocol overhead takes a few percent, Wi-Fi may be slower than the plan, and the server may not deliver at full speed. Using a cable connection and a good server gets you closest to the figure.
Why your speed test seems low
Speed tests report megabits, so a result of 94 Mbit/s on a 100 Mbit/s plan is normal. Real-world factors include distance from the router, other devices, interference, and whether the server you're connecting to is busy.
If you consistently get less than half your plan, test with a cable, close other apps, and try again at different times. Then contact your provider with numbers in hand.
Typical speeds
Mobile 4G often delivers 20 to 50 Mbit/s, 5G can be several hundred, home fibre commonly offers 100 to 1,000 Mbit/s, and a good Wi-Fi 6 link reaches a few hundred in practice. A hard drive transfers around 100 to 200 MB/s, and a fast SSD can exceed 3,000.
Putting numbers side by side shows where the bottleneck is. A 1 Gbit/s internet plan means 125 MB/s at best, which is about what a typical hard drive can write.
Questions
Why is my download slower than my plan?
Overhead, Wi-Fi quality and the server's own speed all take a cut, and your plan is quoted in bits while your browser shows bytes.
Is KiB the same as KB?
No. A kibibyte is 1,024 bytes and a kilobyte is 1,000.