Data Transfer Rate Converter
Converters · Added 15 August 2026
Convert data transfer rates between bits and bytes per second and between decimal and binary prefixes. This is the converter that explains why a 100 Mbps connection downloads at about 12.5 MB/s — the connection is sold in bits, the download is reported in bytes, and there are eight bits in a byte.
Result
1 Mbit/s in megabyte per second
0.125 MB/s
1 Mbit/s = 0.125 MB/s
The same value in every unit
- Bit per second (bit/s)
- 1,000,000
- Kilobit per second (kbit/s)
- 1,000
- Megabit per second (Mbit/s)
- 1
- Gigabit per second (Gbit/s)
- 0.001
- Terabit per second (Tbit/s)
- 0.000001
- Byte per second (B/s)
- 125,000
- Kilobyte per second (kB/s)
- 125
- Megabyte per second (MB/s)
- 0.125
- Gigabyte per second (GB/s)
- 0.000125
- Kibibit per second (Kibit/s)
- 976.5625
- Mebibit per second (Mibit/s)
- 0.953674316
- Gibibit per second (Gibit/s)
- 0.000931322575
- Kibibyte per second (KiB/s)
- 122.070313
- Mebibyte per second (MiB/s)
- 0.11920929
- Gibibyte per second (GiB/s)
- 0.000116415322
Internet connections are advertised in bits per second and downloads are reported in bytes per second, a factor of eight apart. A 100 Mbps line tops out around 12.5 MB/s — that is the arithmetic working correctly, not the provider under-delivering.
How to use the data transfer rate converter
- 1Enter the transfer rate you have.
- 2Pick its unit — note the capital B for bytes and lowercase b for bits.
- 3Choose the unit you want.
- 4The table shows the same rate in every unit, decimal and binary.
- 5Swap the units to reverse the conversion.
Examples
A 100 Mbps connection
- Input
- 100 Mbit/s
- Result
- 12.5 MB/s · 11.92 MiB/s
The maximum theoretical download rate. Real throughput is lower once protocol overhead is counted.
Gigabit fibre
- Input
- 1 Gbit/s
- Result
- 125 MB/s · 119.21 MiB/s
Fast enough to saturate a mechanical hard drive.
A download manager reading
- Input
- 5 MB/s
- Result
- 40 Mbit/s
Working backwards from what your browser reports to what your provider advertises.
About the data transfer rate converter
Bits, bytes, and a marketing accident
Data rates are quoted in bits per second for a genuine technical reason: the bit is the fundamental unit a communication channel carries, and encoding schemes, error correction and line rates are all naturally described in bits. Storage, by contrast, is organised in bytes, because a byte is the smallest individually addressable chunk of memory in nearly every architecture.
The result is that the two sides of the same activity are measured in units eight apart. Your connection is sold in bits and your files are measured in bytes. It is not a deception — both conventions predate consumer broadband — but the factor of eight makes advertised speeds look considerably more impressive than the download counter that follows.
The only defence is reading the case of the letter carefully. Lowercase b means bits, uppercase B means bytes: 100 Mb/s and 100 MB/s differ by a factor of eight, and the difference between them is one keystroke. Specifications that spell the unit out — 'megabits per second' — are doing their readers a favour.
Why real throughput is always below the line rate
The advertised rate is the raw capacity of the link. Actual useful throughput is lower, and the gap has several components. Protocol overhead is the first: every packet carries headers, and acknowledgements travel back the other way, so a few percent of capacity never carries your payload.
Latency is the second and is often the larger effect on a fast link. TCP sends a window of data and waits for acknowledgement, so on a high-bandwidth, high-latency path the connection spends much of its time waiting rather than sending. This is why a satellite link with generous bandwidth can still feel slow, and why downloading from a distant server is slower than from a nearby one at identical advertised speeds.
Then there is everything outside your control: the source server's own capacity, congestion at any hop along the route, and — most commonly for home users — the wireless link between the router and the device. A gigabit connection reaching a laptop over a congested 2.4 GHz Wi-Fi channel will not deliver gigabit results, and the bottleneck is the last few metres rather than anything the provider supplies.