A walkthrough, end to end.
- 1
Enter file size, transfer speed, or both — solve for the third.
- 2
Pick units: KB/MB/GB/TB for size, Kbps/Mbps/Gbps for speed.
- 3
See expected download time in seconds, minutes, or hours.
Transfer time
Time = size / speed. 1 byte = 8 bits, so divide bytes-per-second by 8 to get bits-per-second.
What you can do with this.
Download estimates
How long will a 50 GB game take on 100 Mbps?
Upload planning
Estimate cloud-backup time.
Streaming sanity check
Compare bitrate against your link speed.
ISP plan comparison
Translate Mbps into 'time to download X'.
Server bandwidth
Plan monthly transfer caps.
Video conferencing
Bandwidth required per participant.
Backup windows
Will the nightly backup finish before morning?
Bandwidth 2026 — what's current
Standard arithmetic; calculator wins for instant unit conversion.
Frequently asked.
ISPs advertise in bits/second (Mbps). File sizes are in bytes (MB). 1 byte = 8 bits.
Real-world transfer is ~85–95% of theoretical. The calculator shows the ideal.
No. All math runs in your browser.
Toggle MB (decimal, 1000²) vs MiB (binary, 1024²). ISPs and OS vendors differ.