Mbps vs MBps: What's the Difference?
Quick answer
Mbps is megabits per second; MBps (or MB/s) is megabytes per second. One byte is eight bits, so divide Mbps by 8 to get MB/s. A 100 Mbps connection downloads at most about 12.5 MB/s.
Internet plans and speed tests use bits; file sizes and download windows use bytes. That's why a game launcher showing "12 MB/s" on a 100 Mbps plan is actually doing fine — it's the same speed written in a different unit.
The rule: divide by 8
| Plan speed | Best-case download |
|---|---|
| 10 Mbps | 1.25 MB/s |
| 50 Mbps | 6.25 MB/s |
| 100 Mbps | 12.5 MB/s |
| 300 Mbps | 37.5 MB/s |
| 500 Mbps | 62.5 MB/s |
| 1 Gbps (1,000 Mbps) | 125 MB/s |
And the other way: multiply MB/s by 8 to get Mbps. A download running at 5 MB/s is using 40 Mbps of your connection.
Use the Mbps to MB/s converter for any other number, or switch the speed test to MB/s with the toggle at the top of the result.
How to tell them apart
- A lowercase b means bits: Mbps, Mb/s.
- An uppercase B means bytes: MBps, MB/s.
- Kilo (k), mega (M) and giga (G) mean thousand, million and billion.
The problem is that people — and some apps — don't always follow the rule. If a number seems eight times too high or too low, the units have probably been mixed up.
Where you'll see each unit
| Bits (Mbps) | Bytes (MB/s) |
|---|---|
| Your broadband plan and contract | Browser download bars |
| Speed tests | Game stores and launchers |
| Router and Wi-Fi specifications | File sizes on your computer and phone |
| Streaming requirements | Cloud storage and backup apps |
Why networks use bits
Data travels over a cable or radio one bit at a time, so networking has always counted in bits. Storage — disks, files, memory — counts in bytes, because computers handle data in byte-sized chunks. Neither is wrong; they just measure different things. Advertisers don't mind that bits also make the number eight times bigger.
The 1,000 vs 1,024 wrinkle
There's a second, smaller source of confusion. Network speeds use decimal units: 1 megabit is exactly 1,000,000 bits. Some operating systems show file sizes in binary units, where a "megabyte" is 1,048,576 bytes (strictly a mebibyte, MiB). The difference is about 5 % at mega and about 7 % at giga — small next to the factor of eight, but it's another reason a download can look a little slower than the maths suggests.
Working out download times
To estimate how long a file will take, convert its size to megabits (GB × 8,000) and divide by your speed in Mbps. For example, a 20 GB game on a 200 Mbps connection is 160,000 megabits ÷ 200 = 800 seconds, or about 13 minutes. Or skip the maths with the download time calculator.
Real downloads are often a little slower than the line speed because the server, Wi-Fi or other devices limit them — see why is my internet so slow. To see whether your plan itself is fast enough, read what is a good internet speed.
Common mix-ups
- "My download is eight times slower than my plan." You're probably comparing a browser's MB/s with your plan's Mbps. Multiply by 8 and check again.
- "My router says 1,200 Mbps but my speed test shows 300." The router figure is the Wi-Fi link rate — a theoretical maximum for the radio — not your internet speed. Real throughput is always lower.
- "A 1 GB file should take 10 seconds on 100 Mbps." 1 GB is 8,000 megabits, so it takes about 80 seconds — and a little more in practice.
- Data caps are counted in bytes (GB), while speeds are in bits. A 100 GB cap is 800,000 megabits of transfer.
Kbps, Mbps and Gbps
The same divide-by-8 rule works at every scale: 800 Kbps is 100 KB/s, 8 Mbps is 1 MB/s, and 8 Gbps is 1 GB/s. Older connections and some mobile data limits are still quoted in Kbps; the fastest fibre plans in Gbps. Multiply by 1,000 to step up a unit, and divide by 1,000 to step down.