Data Transfer Time Calculator
Calculate accurate file transfer durations across network protocols. Supports custom overheads, interface standards (WiFi 7, Thunderbolt 5), and massive datasets.
About
Network engineers and DevOps professionals frequently underestimate transfer windows by confusing decimal units with binary ones or ignoring protocol overhead. This tool addresses those discrepancies. It calculates the theoretical and realistic time required to move data across specific interfaces, from legacy USB 2.0 to modern fiber optic backbones (OC-768).
Accuracy depends on distinguishing between storage size and transmission speed. Storage usually defaults to binary prefixes while bandwidth uses decimal. We account for TCP/IP packet overhead which typically reduces effective throughput by 3% to 15% depending on the MTU size and congestion.
Formulas
The core calculation requires normalizing units to bits per second. Note the distinction between Bytes (B) and bits (b).
Where Overhead represents protocol headers (TCP/IP, Ethernet frame). For standard internet transmission, we often estimate:
Reference Data
| Interface / Standard | Raw Speed | Effective Speed (approx) | Time for 1 TB (Theoretical) |
|---|---|---|---|
| USB 2.0 | 480 Mbps | 35 MB/s | ~8.3 Hours |
| USB 3.0 (3.2 Gen 1) | 5 Gbps | 450 MB/s | ~38 Minutes |
| Gigabit Ethernet (1GbE) | 1000 Mbps | 115 MB/s | ~2.5 Hours |
| WiFi 6 (802.11ax) | 9.6 Gbps (Max) | ~800-1200 MB/s | ~15-20 Minutes |
| Thunderbolt 3/4 | 40 Gbps | 3.5-4 GB/s | ~4 Minutes |
| PCIe 4.0 x16 | 252 Gbps | 31.5 GB/s | ~32 Seconds |
| OC-768 (Fiber) | 39.8 Gbps | 4.9 GB/s | ~3.5 Minutes |
| Starlink (User Terminal) | 100-200 Mbps | 12-25 MB/s | ~12-24 Hours |