Download time calculator
Enter the file size and your connection speed. A 4 GB file at 100 Mbps downloads in 5 min 20 s at best.
- Checked on thousands of cases
- Sources: NIST
- Updated November 6, 2026
Theoretical time
That is 32,000,000,000 bits to transfer
Minimum time with no loss: in practice, expect a little more.
Quick challenge
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Test yourself: every answer is computed by the tool, and the wrong choices are the most common traps.
How it works
Formula: Time (s) = size (bytes) × 8 ÷ speed (bits/s)
Speeds are given in bits per second and sizes in bytes, with 1 byte = 8 bits. So the size is converted to bits, then divided by the speed: 4 GB = 32,000,000,000 bits, divided by 100,000,000 bits per second, makes 320 seconds. The prefixes kilo, mega and giga mean 1,000, 1,000,000 and 1,000,000,000; the binary prefixes kibi, mebi and gibi (KiB, MiB, GiB) mean 1,024, 1,048,576 and 1,073,741,824. The result is a theoretical time: protocol overhead, Wi-Fi and the server often make a real download longer.
Download time by file size and speed
| Size | 10 Mbps | 50 Mbps | 100 Mbps | 500 Mbps | 1,000 Mbps |
|---|---|---|---|---|---|
| 100 MB | 1 min 20 s | 16 s | 8 s | 1.6 s | 0.8 s |
| 1 GB | 13 min 20 s | 2 min 40 s | 1 min 20 s | 16 s | 8 s |
| 5 GB | 1 h 06 min 40 s | 13 min 20 s | 6 min 40 s | 1 min 20 s | 40 s |
| 50 GB | 11 h 06 min 40 s | 2 h 13 min 20 s | 1 h 06 min 40 s | 13 min 20 s | 6 min 40 s |
| 100 GB | 22 h 13 min 20 s | 4 h 26 min 40 s | 2 h 13 min 20 s | 26 min 40 s | 13 min 20 s |
Frequently asked questions
What is the difference between MB and Mb?
MB (megabyte) measures a size, Mb or Mbit (megabit) measures a speed: 1 MB = 8 Mbit. A 100 Mbps connection therefore downloads at most 12.5 MB per second.
How long does 1 GB take to download?
At 10 Mbps: 13 min 20 s. At 100 Mbps: 1 min 20 s. At 1 Gbps: 8 s. These are theoretical times, with no loss at all.
Why is my download slower than expected?
The advertised speed is a maximum. Part of it carries protocol data, other devices share the connection, Wi-Fi loses speed with distance, and the server may cap the speed itself.