Transfer Time
7m 29s
Effective Speed
11.25 MB/s
File Size
4.7 GB
Accounts for TCP/IP headers, retransmissions, and protocol overhead. 10% is typical for most transfers.
| File Type | Typical Size |
|---|---|
| MP3 Song (5 min) | 5 MB |
| HD Photo (DSLR) | 25 MB |
| HD Movie (1080p) | 4.7 GB |
| 4K Movie | 20 GB |
| Game Install | 50–100 GB |
| Full Backup (1 TB) | 1 TB |
Inputs
Result
A 4.7 GB movie file contains about 40.4 billion bits. At 100 Mbps with 10% overhead, the effective throughput is 90 Mbps (11.25 MB/s), giving a transfer time of approximately 7 minutes and 29 seconds.
Inputs
Result
A 50 MB photo album at 25 Mbps with 10% overhead transfers at 2.81 MB/s effective speed, completing in about 19 seconds.
Inputs
Result
A full 1 TB backup over Gigabit Ethernet at 90% efficiency takes about 2 hours and 43 minutes at 112.5 MB/s sustained throughput.
Divide the file size in bits by your effective connection speed in bits per second. A 1 GB file over a 100 Mbps connection takes about 89 seconds at raw speed, or roughly 99 seconds with 10% protocol overhead. Always account for overhead from TCP/IP headers and retransmissions.
| File Size | At 25 Mbps | At 100 Mbps | At 1 Gbps |
|---|---|---|---|
| 100 MB | 37 sec | 9 sec | < 1 sec |
| 1 GB | 6 min | 1.5 min | 9 sec |
| 10 GB | 59 min | 15 min | 1.5 min |
| 100 GB | 9.8 hr | 2.5 hr | 15 min |
Internet speeds are advertised in megabits per second (Mbps), but file sizes are measured in megabytes (MB). Since 1 byte = 8 bits, a 100 Mbps connection transfers at most 12.5 MB/s. Protocol overhead, network congestion, WiFi interference, and server-side limits further reduce actual throughput to 60–80% of the rated speed.
| Factor | Speed Loss | Example at 100 Mbps |
|---|---|---|
| Bits to Bytes | 87.5% | 12.5 MB/s max |
| TCP Overhead | 5–10% | 11.25–11.88 MB/s |
| WiFi (same room) | 10–20% | 10–11.25 MB/s |
| WiFi (through walls) | 30–50% | 6.25–8.75 MB/s |
KB, MB, and GB measure file size in bytes (binary: 1 KB = 1,024 bytes). Kbps, Mbps, and Gbps measure transfer speed in bits per second (decimal: 1 Mbps = 1,000,000 bits/s). To convert speed to file transfer rate, divide by 8. A 100 Mbps connection moves 12.5 MB per second.
USB 3.0 transfers at 5 Gbps (theoretical), about 5x faster than Gigabit Ethernet (1 Gbps) and 4–6x faster than WiFi 6 (1.2 Gbps max). However, real-world USB 3.0 speeds peak around 400 MB/s due to controller overhead. For network transfers, Gigabit Ethernet delivers the most consistent speed at around 110–120 MB/s.
| Interface | Rated Speed | Real-World Speed | 1 GB Transfer |
|---|---|---|---|
| WiFi 5 | 866 Mbps | ~50 MB/s | ~20 sec |
| WiFi 6 | 1,200 Mbps | ~90 MB/s | ~11 sec |
| Gigabit Ethernet | 1 Gbps | ~115 MB/s | ~9 sec |
| USB 3.0 | 5 Gbps | ~400 MB/s | ~2.5 sec |
| Thunderbolt 3 | 40 Gbps | ~2,800 MB/s | < 1 sec |
For most transfers, 10% overhead is a reasonable default. TCP/IP headers add 5–8%, and retransmissions add another 1–3%. WiFi transfers have higher overhead of 15–30% due to frame overhead and contention. VPN tunnels add 5–15% extra. For local USB or Thunderbolt transfers, use 3–5%.
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Last Updated: Mar 9, 2026
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