Bandwidth Converter
Convert a network speed between bits and bytes: Mbps, MB/s, MiB/s and more, each shown in full.
Bits per second
How internet plans and network links are rated.
bps
100,
Kbps
100,
Mbps
100
Gbps
0.1
Tbps
0.0001
Bytes per second
8 bits to the byte, and 1,000 bytes to the KB.
B/s
12,
KB/s
12,
MB/s
12.5
GB/s
0.0125
TB/s
0.0000125
Binary bytes per second
1,024 bytes to the KiB: Windows counts file sizes this way, while it writes KB, MB and GB.
KiB/s
12,
MiB/s
11.920929
GiB/s
0.0116415
TiB/s
0.0000113687
Data moved at 100 Mbps
| Kept up for | Decimal | Binary | Bytes |
|---|---|---|---|
| 1 hour | 45 GB | 41.91 GiB | 45,000,000,000 |
| 24 hours | 1.08 TB | 1,006 GiB | 1,080,000,000,000 |
| 30 days | 32.4 TB | 29.47 TiB | 32,400,000,000,000 |
At the full speed the whole time. Over Ethernet, the TCP, IP and frame headers take about 5%, so a download moves at most about 95% of these figures.
Common Internet & Network Speeds
| Connection | Mbps | MB/s | GB per hour |
|---|---|---|---|
| 2 | 0.25 | 0.9 | |
| 24 | 3 | 10.8 | |
| 50 | 6.25 | 22.5 | |
| 100 | 12.5 | 45 | |
| 300 | 37.5 | 135 | |
| 1,000 | 125 | 450 | |
| 2,500 | 312.5 | 1,125 | |
| 10,000 | 1,250 | 4,500 |
Mobile speeds are typical ones, which vary by country, network and year; the rest are what the link is rated at. Select a connection to convert it.
Bits vs Bytes
Network speeds are counted in bits per second (bps, Kbps, Mbps, Gbps), while file sizes are counted in bytes (B, KB, MB, GB). A byte is 8 bits, so divide a speed in Mbps by 8 for MB/s: a 100 Mbps plan moves at most 12.5 MB/s, and nearer 11.8 MB/s once TCP runs over Ethernet. Internet providers advertise in bits; browsers and download managers show bytes.
Windows counts file sizes in units of 1,024 bytes while it labels them KB, MB and GB, and Chrome and Firefox count a download's size and speed the same way, so a download at 12.5 MB/s shows as about 11.9 "MB/s" in Chrome and 11.9 "MB/sec" in Firefox; the binary boxes above give those figures. Every value is shown whole, so 100 Mbps reads 100,000,000 bps. For how long one file takes, see the Download Time Calculator, and for the units in depth, Mbps vs MB/s: network speed units explained.
Built and maintained by Meet Shah · Last updated
What this tool is used for
- Converting a plan's speed in megabits into the megabytes per second a download shows.
- Checking a download's speed in Chrome or Firefox, which count in units of 1,024 and label them MB.
- Working out how much data a link can move in an hour, a day or 30 days, against a data cap.
- Comparing two connection specifications quoted in different units.
- Checking whether a measured speed matches what was sold.
Frequently Asked Questions
- Why is my 100 Mbps connection only 12 MB/s?
- Because a byte is eight bits: speeds are quoted in bits and file sizes in bytes. 100 Mbps ÷ 8 = 12.5 MB/s at most, and about 11.8 MB/s once TCP runs over Ethernet, whose headers take about 5%. Only the case of the b tells them apart: Mb is megabits, MB megabytes.
- Does this use 1000 or 1024 as the multiplier?
- Both, kept apart. The bit and byte units are decimal, as network speeds always are: 1 Kbps is 1,000 bits per second and 1 KB/s 1,000 bytes. The binary units, KiB/s to TiB/s, count 1,024, as Windows does for file sizes while it labels them KB, MB and GB. The gap is 2.4% at kilo and 7.4% at giga.
- How do I work out a download time?
- Convert the file size to bits (bytes × 8) and divide by the speed in bits per second. A 5 GB file at 100 Mbps is 40,000 megabits ÷ 100 = 400 seconds, 6 minutes 40 seconds at the full rate; with the 5% that TCP over Ethernet takes, about 7 minutes. A 5 GB file as Windows counts it, 5 GiB, takes 7.4% longer.
- Why is real throughput always below the rated speed?
- Because the rating is the line's rate, and headers share it with your data. Over Ethernet, frame, IP and TCP headers take about 5% of a full-size packet, so a wired download peaks near 95% of the rating; resent packets take more. A Wi-Fi rating is its radio's best case, and real throughput is often half that or less.
- Is 5G actually faster than a 1 Gbps fibre line?
- At its peak it can be: millimetre-wave 5G has been measured above 1 Gbps. But a cell's capacity is shared by everyone on it and falls with distance and walls, so typical 5G speeds are lower, like the table's 300 Mbps, while fibre holds its rate. Fibre's latency is usually lower too, which calls and games notice more.
- How much data can a 100 Mbps line move in a month?
- 32.4 TB in 30 days, if it ran at the full rate the whole time: 12.5 MB/s × 2,592,000 seconds. Windows would count that as 29.47 TiB, labelled TB. The converter shows the data for an hour, a day and 30 days at any speed; a real line, idle much of the day, moves far less.
Common errors and gotchas
- Confusing bits with bytes: Mb and MB differ by a factor of eight.
- Assuming a line speed equals achievable throughput, which protocol overhead reduces.
- Mixing decimal and binary prefixes, where a megabyte may mean 10^6 or 2^20 depending on context.
- Assuming upload matches download, when many consumer links, cable and DSL among them, are asymmetric.
- Comparing a peak rate against a sustained one as if they were the same measurement.