Uploads and backup
How long does it take to upload 2 TB at 100 Mbps?
46 h 49 min
to upload 2 TB at 100 Mbps, best case. Typical: 2 days 8 h (at 80 % efficiency, our estimate for Wi-Fi and busy servers).
2 TB is a full laptop plus an external drive. Even on a 100 Mbps upload, which usually means fibre, the first backup takes about two days of continuous uploading.
Uploading only overnight, 8 hours a night, it takes about 5.9 nights.
The arithmetic
- 2,000 GB × 8 bits per byte = 16,000 gigabits (16,000,000,000,000 bits)
- 100 Mbps = 100,000,000 bits per second = 12.5 MB/s at most
- 16,000,000,000,000 ÷ 100,000,000 = 160,000 s = 44 h 27 min with zero overhead
- TCP/IP and Ethernet framing use about 5 % of the line (1,460 data bytes per 1,538 on the wire): 160,000 ÷ 0.949 = 46 h 49 min
If the size is really 2,000 GiB (some stores and Windows label GiB as GB), it is 7.4 % bigger: 2 days 2 h best case.
| Speed | Best case (95 %) | Typical (80 %, estimate) |
|---|---|---|
| 10 Mbps | 19 days 12 h | 23 days 4 h |
| 25 Mbps | 7 days 19 h | 9 days 6 h |
| 50 Mbps | 3 days 22 h | 4 days 15 h |
| 100 Mbps | 46 h 49 min | 2 days 8 h |
| 300 Mbps | 15 h 36 min | 18 h 31 min |
| 500 Mbps | 9 h 22 min | 11 h 7 min |
| 1,000 Mbps | 4 h 41 min | 5 h 33 min |
Sources and assumptions
- Overhead: 94.9 % efficiency from TCP/IPv4 on 1,500-byte Ethernet frames (computed); 80 % 'typical' is our estimate.