Formula
Size is converted to bits, then divided by bits per second:
seconds = file bytes × 8 / (Mbps × 1,000,000)
One megabyte is 1,000,000 bytes and one gigabyte is 1,000,000,000 bytes. The clock is rounded to the nearest second. Upload overhead, a monthly data total, streaming hours, and a game install are separate pages because each one adds an input this division does not have.
Assumptions
- The speed stays at the number you type for the whole transfer.
- Megabytes and gigabytes are decimal, matching network speeds, not 1,024-based gibibytes.
- Protocol overhead and other devices sharing the line are not subtracted.
Worked example
A 2 GB file at 50 Mbps takes 5:20.
Input definitions
- File size
- How large the file is, in decimal megabytes or gigabytes.
- Speed
- Megabits per second. A megabit is one eighth of a decimal megabyte.
Limitations
A speed test and a finished download can differ. This page does not model pauses, packet loss, or a data cap.
Questions
Why is a megabyte not 1,024 kilobytes here?
Connection speeds are sold in decimal bits. Using 1,000-based bytes keeps the division consistent with Mbps.
Can I estimate an upload?
The upload page divides by the speed that remains after a protocol overhead. This page is the raw division, with no overhead subtracted.