Formula
Data bytes × 8 ÷ (Mbps × efficiency) gives the transfer duration in seconds. This tool uses decimal TB: 10¹² bytes.
Real jobs can take longer. Small files, encryption, compression, source and destination disks, Wi-Fi congestion, verification, and retries are outside this simple transfer model.
Choosing a speed
Use a sustained measurement from a long file copy when available. Convert MB/s to Mbps by multiplying by eight.
Related checks
Combine this estimate with the 3-2-1 backup guide and RAID capacity calculator.