WIN-J TOOLS LOCAL & SIMPLE
Download time calculator
Estimate transfer time from file size and connection speed. Distinguish Mbps from MB/s and GB from GiB, and adjust the assumed effective speed.
Result
This tool does not send entered values or selected files to a server. Save any results you need before closing the tab.
How to use
- Enter the file size and unit, distinguishing GB from GiB.
- Enter the transfer speed and unit. Connection plans often use Mbps or Gbps, while download dialogs may show MB/s.
- Set an effective-speed percentage and calculate. The estimate assumes that speed stays constant.
Worked example
A 1 GB file at 100 Mbps takes 80 seconds in theory. At 80% effective speed it takes 100 seconds. A 1 GiB file is larger than 1 GB and takes longer at the same speed.
Method and limitations
Multiply bytes by 8 to obtain bits, then divide by effective bits per second. KB, MB and GB use powers of 1000; KiB, MiB and GiB use powers of 1024. The hours/minutes/seconds display rounds total seconds upward.
This does not measure your connection. Server limits, Wi-Fi interference, shared connections and setup time can change real transfer times. The effective-speed percentage is an assumption you choose.
Frequently asked questions
Is 100 Mbps the same as 100 MB/s?
No. One byte is eight bits, so 100 Mbps corresponds to a theoretical 12.5 MB/s. Pay attention to uppercase B and lowercase b.