How to use this calculator
- Enter or choose data transferred.
- Enter or choose data unit.
- Enter or choose time taken.
- Enter or choose time unit.
- Enter or choose link speed (optional).
- The throughput updates as you type. Use Copy result or Share to keep it.
Method
Throughput (bit/s) = Bytes × 8 ÷ Seconds; Mbps = bit/s ÷ 10⁶; MB/s = bytes/s ÷ 10⁶; MiB/s = bytes/s ÷ 2²⁰
- Bytes
- data moved, with 1 GB = 10⁹ bytes and 1 GiB = 2³⁰ bytes
- Seconds
- elapsed transfer time
Worked example
- 1 GB = 10⁹ bytes = 8 × 10⁹ bits.
- 8 × 10⁹ bits ÷ 10 s = 8 × 10⁸ bit/s = 800 Mbps = 100 MB/s.
- 100 × 10⁶ ÷ 1,048,576 = 95.367 MiB/s; 800 of 1,000 Mbps is 80%.
Moving 1 GB in 10 seconds is 800 Mbps (100 MB/s), 80% of a gigabit link.
What the result means
Expect application throughput a few per cent below the line rate because of Ethernet, IP and TCP headers. Far lower results usually point to latency with a small TCP window, disk speed, Wi-Fi, or a busy link.
Assumptions and limits
- The time covers only the transfer itself.
- Link speeds use SI prefixes (1 Mbps = 10⁶ bit/s), as network equipment does.
- A single average hides bursts and stalls during the transfer.
Questions
Is 100 MB/s the same as 100 Mbps?
No. A byte is 8 bits, so 100 MB/s is 800 Mbps. Lower-case b means bits, upper-case B means bytes.
Why does my file manager show a lower MB/s figure?
Many operating systems divide by 1,048,576 (MiB) but label it MB, which reads about 4.6% lower than decimal megabytes.