Megabit/s to Megabyte/s
Convert megabit/s (Mbps) to megabyte/s (MB/s) instantly. Convert connection speeds with confidence.
Megabit/s → Megabyte/s
0.125
MB/s
1 Mbps = 0.125 MB/s
Frequently asked questions
Because those are the same speed expressed in different units. Network rates are quoted in megabits per second and file sizes in megabytes, and there are 8 bits in a byte — so 100 Mbps is 12.5 MB/s at best. In practice you will see 10-11 MB/s once protocol overhead is counted, which typically consumes 10-20% of the line rate.
About 80 seconds on a 100 Mbps connection at the theoretical maximum of 12.5 MB/s, and realistically closer to 95-100 seconds. On a 50 Mbps connection it is roughly three minutes, and on 1 Gbps about 8 seconds.
The bottleneck is usually not the ISP. Wi-Fi is the most common constraint, particularly on a congested 2.4 GHz band. Beyond that: the server at the other end may be rate-limiting, the local segment may be contended at peak hours, an older device or a 100 Mbps Ethernet port caps everything behind it, and a slow drive can bottleneck a very fast connection. Test over Ethernet to see what the line itself provides.
A hundred megabits is twelve and a half megabytes
A 100 Mbps connection downloads at a maximum of 12.5 MB per second. Not 100 MB/s — the difference is a factor of eight, and it is the single most common misunderstanding about internet speed.
MB/s = Mbps ÷ 8
Bits and bytes
A bit is a single binary digit. A byte is eight bits, and it is the unit in which file sizes are measured.
Network speeds are quoted in bits per second — a convention inherited from telecommunications, where signalling was measured in bits long before bytes existed as a standard grouping. File sizes are measured in bytes. So every calculation of "how long will this download take" requires a division by eight.
The notation is the only thing distinguishing them, and it is subtle:
- Mbps or Mb/s — megabits per second, a rate
- MB/s — megabytes per second, a rate
- MB — megabytes, a quantity
ISPs advertise in megabits because it produces a number eight times larger. That is not deceptive — it is the industry convention — but it consistently surprises people who expect a 100 Mbps connection to move a 1 GB file in ten seconds.
Real download times
At 100 Mbps, with a theoretical 12.5 MB/s:
- 1 GB file — about 80 seconds at best
- 5 GB file — about 7 minutes
- 50 GB game — about 67 minutes
And those are theoretical maxima. Real throughput typically reaches 80–90% of the line rate because of protocol overhead: TCP headers, IP headers, Ethernet framing, acknowledgements and retransmissions all consume capacity. Expect roughly 10–11 MB/s on a good 100 Mbps connection.
Common conversions
- 10 Mbps = 1.25 MB/s
- 50 Mbps = 6.25 MB/s
- 100 Mbps = 12.5 MB/s
- 300 Mbps = 37.5 MB/s
- 1 Gbps = 125 MB/s
What actually limits your speed
A connection rarely delivers its rated speed, and the bottleneck is usually not the ISP:
Wi-Fi. The most common constraint. A 2.4 GHz connection in a congested area may deliver a fraction of a 100 Mbps line. Testing over Ethernet is the only way to know what the line itself provides.
The server at the other end, which may be rate-limiting or simply distant.
Contention, where the local segment is shared and evening peak hours reduce available throughput.
Device limits — an older laptop's Wi-Fi radio or a 100 Mbps Ethernet port caps everything behind it.
Storage write speed, which can bottleneck a very fast connection when writing to a slow drive.
Bandwidth is not latency
A distinction worth holding. Bandwidth is how much data can move per second; latency is how long a single packet takes to make the round trip.
For large downloads, bandwidth dominates. For video calls, gaming and general web browsing responsiveness, latency matters more — a 1 Gbps connection with 200 ms latency feels worse for interactive use than a 50 Mbps connection at 20 ms.