SwiftNetScanDownload Time Calculator
Enter a file size and your connection speed to see how long the transfer should take. Works for uploads too — just enter your upload speed.
Estimated transfer time
7m 24s
12.5 MB/s theoretical throughput
How the calculation works
Transfer time equals file size in bits divided by throughput in bits per second. Because connection speeds are advertised in megabits and file sizes are stored in megabytes, the two differ by a factor of eight. TCP, TLS and HTTP framing then consume a further 5–15%, which is why we apply a 10% correction by default.
- 1 byte = 8 bits, so 100 Mbps ≈ 12.5 MB/s at best.
- WiFi typically delivers 50–70% of a wired link's throughput.
- A saturated upload channel slows downloads by delaying acknowledgements.
- Server-side limits often cap the transfer well below your plan.
Frequently Asked Questions
Get answers to common questions about internet speed testing.