Mbps to MB/s Converter
Convert megabits per second to megabytes per second. Divide by 8 — and understand why the number on your ISP advert is never the number your download manager shows.
The one conversion that matters
Every unit conversion on this page comes down to a single fact: one byte is eight bits. Network engineers measure capacity in bits because the physical layer transmits bits, while file sizes and disk throughput are measured in bytes because that is what an application reads and writes. Neither convention is wrong, but mixing them without the factor of 8 is where almost every confusion about link speed originates.
MB/s = Mbps ÷ 8 100 Mbps ÷ 8 = 12.5 MB/s 10 Mbps ÷ 8 = 1.25 MB/s 1 Mbps ÷ 8 = 0.125 MB/s = 125 KB/s 1 Gbps ÷ 8 = 125 MB/s
The reverse is just as simple: MB/s × 8 = Mbps. A copy running at 112 MB/s is saturating a 1 Gbps link, because 112 × 8 = 896 Mbps and Ethernet has protocol overhead on top of that.
Why your download is slower than the advertised speed
This is the question behind most Mbps-to-MB/s searches, so it is worth answering properly. The short version is that nothing is broken — you are comparing two different units, and then losing a little more to protocol overhead.
Example: a 100 Mbps fibre connection
100 Mbps advertised ÷ 8 = 12.5 MB/s theoretical maximum
minus TCP/IP and Ethernet overhead ≈ 11.5–12.0 MB/s realistic
If a 20 GB download runs at 11.5 MB/s it finishes in 20,000 ÷ 11.5 ≈ 1,739 seconds, or about 29 minutes. Against the theoretical 12.5 MB/s it would take 27 minutes. The 7% gap is protocol overhead, not a fault.
The overhead comes from the per-packet costs: Ethernet framing, the IP header, the TCP header and acknowledgements travelling in the opposite direction. Typical TCP efficiency on a clean link is around 94% of the raw bit rate. The bandwidth calculator lets you apply an efficiency figure so the estimate reflects this.
Other factors that reduce real throughput below the 12.5 MB/s ceiling: the far-end server limiting the transfer, a single TCP stream that cannot fill the link over a long distance, Wi-Fi contention, disk write speed and CPU load in the client.
Bits, bytes and units that look similar
The notation is unforgiving. These four strings differ only in capitalisation, and they mean four different things:
| Unit | Means | Relation to bits/s |
|---|---|---|
| Mbps | Megabits per second | 1,000,000 bits/s |
| MB/s | Megabytes per second | 8,000,000 bits/s |
| MBps | Megabytes per second (same as MB/s) | 8,000,000 bits/s |
| Mbit/s | Megabits per second (same as Mbps) | 1,000,000 bits/s |
| MiB/s | Mebibytes per second (binary) | 8,388,608 bits/s |
| Mib/s | Mebibits per second (binary) | 1,048,576 bits/s |
There is no room for interpretation when the units are written correctly, but plenty when they are not.
Common mistakes
- Dividing by 10. Some people assume the difference is a factor of ten because the units look similar. Eight is the correct factor, always, because a byte is eight bits and not ten.
- Confusing Mbps with MBps in a contract. An ISP quoting 100 MB/s means 800 Mbps, which is far beyond most consumer connections. Check the capitalisation before signing.
- Mixing decimal and binary units in one comparison. Comparing a decimal Mbps figure against an operating system's MiB/s display adds a further 4.9% discrepancy on top of the factor of 8.
- Expecting the full theoretical rate. Protocol overhead means real TCP throughput tops out at roughly 94% of the raw link rate, before you account for the server at the other end.
Also: MB/s to Mbps Converter · Gbps to MB/s Converter · IP to Binary Converter · IP to Decimal Converter · IP to Hex Converter
Reference: common link speeds
| Link | Mbps | MB/s (theoretical) | Typical real-world |
|---|---|---|---|
| Old ADSL | 8 Mbps | 1.0 MB/s | 0.9 MB/s |
| Basic broadband | 24 Mbps | 3.0 MB/s | 2.8 MB/s |
| Superfast fibre | 80 Mbps | 10.0 MB/s | 9.4 MB/s |
| Standard fibre | 100 Mbps | 12.5 MB/s | 11.5–12.0 MB/s |
| Fast fibre | 200 Mbps | 25.0 MB/s | 23–24 MB/s |
| Gigabit fibre | 1,000 Mbps | 125 MB/s | 115–118 MB/s |
| 2.5 GbE LAN | 2,500 Mbps | 312.5 MB/s | 290 MB/s |
| 10 GbE LAN | 10,000 Mbps | 1,250 MB/s | 1,100–1,180 MB/s |
| Wi-Fi 5 (practical) | 400 Mbps | 50 MB/s | 35–45 MB/s |
| Wi-Fi 6 (practical) | 900 Mbps | 112.5 MB/s | 70–85 MB/s |
The gap between the theoretical and real-world columns is protocol overhead plus the limits of the other end of the connection. On a LAN transfer the gap is close to the TCP/IP overhead figure; on an internet transfer the remote server is usually the binding constraint.
Related: MB/s to Mbps, Gbps to MB/s, transfer time calculator, TCP throughput calculator.
Frequently asked questions
How do I convert Mbps to MB/s?
Divide by 8. A 100 Mbps connection transfers 12.5 MB/s, because one byte is eight bits. The formula is MB/s = Mbps ÷ 8.
Why is there a factor of 8?
Network speeds are measured in bits per second and file sizes are measured in bytes. A byte is eight bits, so a link carrying 1,000,000 bits each second carries 1,000,000 ÷ 8 = 125,000 bytes per second, which is 125 KB/s or 0.125 MB/s.
Why does my 100 Mbps connection only reach about 12 MB/s?
Because 100 Mbps is 12.5 MB/s, and after TCP/IP overhead, Ethernet framing and protocol acknowledgements you typically see around 11.5 to 12 MB/s in practice. The line is delivering the speed it advertises — the units on the two sides of the comparison are simply different. This is the single most common source of 'my internet is slow' complaints.
What is the difference between Mbps and MB/s in writing?
The capitalisation carries the meaning. A lowercase b is a bit and an uppercase B is a byte, so Mbps is megabits per second and MB/s is megabytes per second. The same rule applies to Gb versus GB and Kb versus KB. When the capitalisation is dropped entirely, the value is ambiguous and often off by a factor of eight.
Does 1 MB equal exactly 1,000,000 bytes?
In networking and storage marketing, yes — MB is defined as 10^6 bytes. The binary equivalent is the mebibyte (MiB), which is 2^20 = 1,048,576 bytes. This 4.9% difference is why a 1 TB drive shows as about 931 GiB in an operating system. This converter uses the decimal definitions, which is the correct convention for link speeds.
How do I convert MB/s back to Mbps?
Multiply by 8. A transfer running at 12.5 MB/s is using 100 Mbps of link capacity. The MB/s to Mbps converter does this direction directly.