Capacity and transfer time calculator (GB ↔ GiB)
Convert between GB and GiB (and TB and TiB), and work out how long a transfer takes at a speed you enter.
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How to use
- Conversion: enter a value and its unit; every unit is listed.
- Transfer time: enter the data size and your speed with units. You can fill an example speed, but the numbers are only examples; type your measured one.
Worked example
A drive sold as 1 TB holds 1,000,000,000,000 bytes = 931.3 GiB, which is what many operating systems show.
100 GB at 500 MB/s = 100,000 MB ÷ 500 = 200 s (3 min 20 s). 1 GB at 8 Mbps = 1 MB/s, so 1,000 s.
Limits
- KB/MB/GB/TB are powers of 1000; KiB/MiB/GiB/TiB are powers of 1024. Some tools label 1024-based sizes “GB”.
- Real transfers are slower than the headline speed: many small files, overhead, drive caches, and the slowest link all matter. The result is an ideal-speed estimate.
- This page does not test your speed; nothing is sent to a server.
Your inputs and results stay in this browser. Nothing is sent to a server.