Data Transfer Rate Converter
Convert data transfer rates between bit-based network units (bps, Kbps, Mbps, Gbps, Tbps) and byte-based file units (B/s, KB/s, MB/s, GB/s), and estimate how long a download will take. The catch that trips everyone up is the bit/byte gap: internet plans are sold in megabits, but files are measured in megabytes, and there are eight bits to a byte — so a 100 Mbps line moves about 12.5 MB per second at best. Enter a file size to see the estimated transfer time at your chosen rate.
How to use this tool
- Enter the transfer rate.
- Choose the unit you have and the unit you want (bit-based or byte-based).
- Optionally enter a file size to estimate the download time.
- Read the converted rate, the full equivalents, and the time estimate.
- Remember to divide megabits by 8 to get the megabytes per second you actually see.
The formula
Transfer rates are counted per second. Networks are quoted in bits per second (Mbps), while files and drives are measured in bytes; dividing a bit rate by 8 gives the byte rate, and dividing a file size by the byte rate gives the transfer time.
bytes_per_sec = bits_per_sec ÷ 8
download_time = file_size_bits ÷ rate_bits_per_sec- bps
- Bits per second (network convention)
- B/s
- Bytes per second (file convention)
A 100 Mbps connection moves at most about 12.5 MB/s, so a 1 GB file takes roughly 80 seconds at full speed — before real-world overhead.
Worked examples
Plan vs reality
- Given
- 100 Mbps
- Result
- 12.5 MB/s
A 100 megabit connection carries 12.5 megabytes per second, because there are 8 bits in a byte.
Download time
- Given
- 1 GB at 100 Mbps
- Result
- ≈ 80 s
A 1 GB file is 8 gigabits; at 100 Mbps that is about 80 seconds at full speed.
Fast link
- Given
- 1 Gbps
- Result
- 1000 Mbps
A gigabit per second is 1000 megabits per second, or about 125 MB/s.
Frequently asked questions
Plans are advertised in megabits per second, but download managers show megabytes per second — eight times smaller. A 100 Mbps plan tops out near 12.5 MB/s. On top of that, protocol overhead, network congestion, the server’s speed and your disk all reduce real throughput below the theoretical maximum.
Mbps is megabits per second (lowercase b), the networking unit. MB/s is megabytes per second (uppercase B), the file unit. Since a byte is 8 bits, MB/s is Mbps divided by 8. The capitalisation carries an eightfold difference, so it is worth reading carefully.
Divide the file size (converted to bits) by the transfer rate (in bits per second). This tool does that and formats the result in days, hours, minutes and seconds. It is the best-case time at a constant full rate; real downloads take longer.
Network and transfer rates use the decimal convention: 1 Kbps is 1000 bps, 1 Mbps is 1,000,000 bps, and so on. This tool follows that convention for rates, which is why the numbers line up with how ISPs advertise speeds.
Because different tools report different ones. Speed tests and ISPs use bits (Mbps); file browsers, download managers and cloud apps use bytes (MB/s). Having both, plus the file-size time estimate, lets you move between what your plan promises and what a transfer will actually feel like.
Related tools
Convert bits, bytes, KB, MB, GB, TB and PB under decimal (1000) and binary (1024) standards.
Media Bitrate & File Size CalculatorEstimate video and audio file sizes, required bitrates and storage from duration and quality.
Data Encoding ConverterConvert text between Base64, hexadecimal, binary, URL encoding and Unicode escapes.