# Data transfer rate converter (Mbps to MB/s)

> Convert Mbps to MB/s, Gbps to MB/s and kbps to kB/s. Network speeds are quoted in bits per second; file sizes and download meters in bytes.

Interactive version: https://www.calcopenly.com/conversion/data-transfer-rate-converter
Subject: Unit converters

Network speeds are quoted in bits per second and file sizes in bytes, and a byte is 8 bits, so megabits per second divide by 8 to give megabytes per second. Each rate unit is a fixed number of bits per second, with decimal prefixes (1 Mbit/s = 10⁶ bit/s) kept apart from binary ones (1 MiB/s = 2²⁰ bytes per second).

The default converts a 100 Mbit/s broadband plan to 12.5 MB/s, the most a download can show in megabytes per second, or 11.92 MiB/s in a program that counts in binary units. A 1 Gbit/s connection tops out at 125 MB/s.

Real transfers run below the line rate because every packet carries headers: over Ethernet with TCP/IPv4, at most 1,460 of every 1,538 bytes on the wire are data, 94.9%. The download time calculator applies that overhead to a file size.

## Inputs

- **Value**: A number in the “from” unit, or with its own unit
- **From** (options: bit per second (bit/s), kilobit per second (kbit/s), megabit per second (Mbit/s), gigabit per second (Gbit/s), terabit per second (Tbit/s), byte per second (B/s), kilobyte per second (kB/s), megabyte per second (MB/s), gigabyte per second (GB/s), kibibyte per second (KiB/s), mebibyte per second (MiB/s), gibibyte per second (GiB/s))
- **To** (options: bit per second (bit/s), kilobit per second (kbit/s), megabit per second (Mbit/s), gigabit per second (Gbit/s), terabit per second (Tbit/s), byte per second (B/s), kilobyte per second (kB/s), megabyte per second (MB/s), gigabyte per second (GB/s), kibibyte per second (KiB/s), mebibyte per second (MiB/s), gibibyte per second (GiB/s))

## Results

- Converted value — main result
- Conversion
- Conversion factor
- Exactness

## Formula

$$
\begin{gathered} x_{\text{to}} = x_{\text{from}} \times \dfrac{f_{\text{from}}}{f_{\text{to}}} \\ f = \text{one unit expressed in } \text{bit/s} \end{gathered}
$$

## Worked examples

### 100 Mbit/s in MB/s

- Value: 100 Mbit/s
- From: megabit per second (Mbit/s)
- To: megabyte per second (MB/s)
- **Converted value: 12.5 MB/s**
- Checked against: 100 × 10⁶ bit/s ÷ 8 bit/B ÷ 10⁶ = 12.5

### 1 Gbit/s in MB/s

- Value: 1 Gbit/s
- From: gigabit per second (Gbit/s)
- To: megabyte per second (MB/s)
- **Converted value: 125 MB/s**
- Checked against: 10⁹ / 8 / 10⁶ = 125

### 1 MiB/s in Mbit/s

- Value: 1 MiB/s
- From: mebibyte per second (MiB/s)
- To: megabit per second (Mbit/s)
- **Converted value: 8.388608 Mbit/s**
- Checked against: 2²⁰ × 8 / 10⁶ = 8.388608

### 1 bit/s in kB/s (tiny value)

- Value: 1 bit/s
- From: bit per second (bit/s)
- To: kilobyte per second (kB/s)
- **Converted value: 0.000125 kB/s**
- Checked against: 1 / 8 / 1000 = 0.000125

## Questions

### How many MB/s is 100 Mbps?

12.5 MB/s. Divide megabits per second by 8, because a byte is 8 bits: 100 ÷ 8 = 12.5. Programs that count in binary units show 11.92 MiB/s for the same speed, and protocol overhead takes about another 5%, so expect around 11.9 MB/s on a wired 100 Mbit/s link.

### What is the difference between Mbps and MBps?

Mbps (Mbit/s) is megabits per second; MBps (MB/s) is megabytes per second, 8 times larger. Internet plans and Wi-Fi speeds are sold in Mbps, while browsers and download managers usually show MB/s, so a 50 Mbps plan appears as 6.25 MB/s. The case of the b is the only visible difference.

### How fast is 1 Gbps in MB/s?

125 MB/s: 1,000,000,000 bits ÷ 8 = 125,000,000 bytes per second, which is 119.21 MiB/s in binary units. At that rate a 50 GB download takes 400 seconds, 6 min 40 s, before protocol overhead is added.

### Why is my download slower than my internet speed?

Part of the gap is units and part is overhead. A plan quoted at 100 Mbit/s is 12.5 MB/s at most, and TCP/IP and Ethernet headers use about 5% of that, leaving about 11.9 MB/s. Wi-Fi signal, the far server and other devices on the connection reduce it further, which this converter does not model.

### How many Mbps is 1 MiB/s?

8.388608 Mbit/s. One MiB/s is 1,048,576 bytes per second, and 1,048,576 × 8 = 8,388,608 bits per second. A tool that reports MiB/s therefore shows a number 4.6% lower than the same speed in MB/s.

### How accurate is the data transfer rate converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 4 worked examples whose answers come from independent sources; for example, “100 Mbit/s in MB/s” is checked against 100 × 10⁶ bit/s ÷ 8 bit/B ÷ 10⁶ = 12.5.

### Where does the method come from?

NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors; NIST Handbook 44, Appendix C — General tables of units of measurement; NIST — Prefixes for binary multiples (IEC 80000-13).

## Sources

- [NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C — General tables of units of measurement](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition)
- [NIST — Prefixes for binary multiples (IEC 80000-13)](https://physics.nist.gov/cuu/Units/binary.html)