Data Transfer Time Calculator
Calculate how long it takes to transfer a file over any connection speed.
Enter file size and connection speed to get transfer time.
Data transfer speed and time calculations require careful attention to unit notation. The computing industry uses two parallel conventions — decimal (base 10, used for storage capacity and network speeds) and binary (base 2, used by operating systems for file sizes) — which causes significant confusion.
The fundamental formula:
Transfer Time = File Size ÷ Transfer Speed
Critical unit conversions:
| Unit | Value |
|---|---|
| 1 kilobit (kb) | 1,000 bits |
| 1 megabit (Mb) | 1,000,000 bits |
| 1 gigabit (Gb) | 1,000,000,000 bits |
| 1 kilobyte (KB) | 1,024 bytes = 8,192 bits |
| 1 megabyte (MB) | 1,048,576 bytes |
| 1 gigabyte (GB) | 1,073,741,824 bytes |
Converting file size to bits for transfer calculation:
File Size in Bits = File Size (GB) × 1,073,741,824 × 8
Transfer Time (seconds) = File Size (bits) ÷ Speed (bps)
Worked example: Upload a 4 GB video file on a 100 Mbps internet connection:
- File size: 4 GB × 1,073,741,824 bytes × 8 bits = 34,359,738,368 bits
- Speed: 100 Mbps = 100,000,000 bits per second
- Time: 34,359,738,368 ÷ 100,000,000 = 343.6 seconds ≈ 5 minutes 44 seconds
Note: Real-world speeds are typically 60–80% of advertised speeds due to protocol overhead, network congestion, and latency.
Real-world speed reference:
| Connection | Typical Speed | Time to Transfer 1 GB |
|---|---|---|
| USB 2.0 | 480 Mbps | ~17 seconds |
| USB 3.0 | 5 Gbps | ~1.6 seconds |
| 100 Mbps Ethernet | 100 Mbps | ~85 seconds |
| Gigabit Ethernet | 1,000 Mbps | ~8.5 seconds |
| 5G (typical) | 100–400 Mbps | ~21–85 seconds |
| Wi-Fi 6 (peak) | 9,608 Mbps | < 1 second |
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.