Calculate Download and Transfer Time
Use a stated speed to plan a download, upload or backup. This estimates duration without selecting or transferring a file.
Open the calculatorWork through the task
- Read the data size and its unit. A download listed as 1 GB is not the same quantity as 1 GiB.
- Enter the applicable upload, download or local-copy speed. A link advertised as 100 Mbps transfers bits, not 100 megabytes per second.
- Start at 100% effective speed for the ideal result. If you use a measured payload speed, avoid subtracting the same overhead again.
- Use Required speed to plan a time window, or Transferable size to see how much fits into it.
Checked examples
| Input | Result |
|---|---|
| 1 GB / 100 Mbps | 80 seconds at 100% |
| 1 GiB / 100 Mbps | 85.89934592 seconds at 100% |
| 1 GB / 100 Mbps at 80% | 100 seconds |
| 100 MB / 100 MB/s | 1 second |
Calculation method
Duration = data bits / (nominal bits per second × effective fraction). Required nominal speed divides size by both the allowed time and that fraction; transferable size multiplies speed, time and the fraction. The same efficiency assumption is applied once.
Assumptions and limits
These are planning estimates. A network link can vary, a remote service can throttle, and a storage device can be the bottleneck. The calculator does not measure speeds, predict an exact finish time or transfer any file. Values marked ≈ are display approximations of exact internal arithmetic.
Try these values in the calculator