Download Time Calculator
Estimate how long it takes to download any file at different internet speeds.
Enter file size in MB or GB and connection speed to get the result.
Download Time Calculator
Download time depends on two things: the size of the file and the speed of your connection. The calculation converts both to the same unit — bits — and divides.
Formula:
Download Time (seconds) = File Size (bits) / Connection Speed (bits per second)
Unit conversions:
| Storage unit | Bits |
|---|---|
| 1 byte | 8 bits |
| 1 kilobyte (KB) | 8,000 bits |
| 1 megabyte (MB) | 8,000,000 bits |
| 1 gigabyte (GB) | 8,000,000,000 bits |
| 1 terabyte (TB) | 8,000,000,000,000 bits |
Note: This calculator uses SI decimal units (1 MB = 1,000,000 bytes), which is how internet speeds are marketed.
Speed reference guide:
| Connection type | Typical speed |
|---|---|
| 3G mobile | 1 – 10 Mbps |
| Home broadband (entry) | 25 – 50 Mbps |
| Home broadband (standard) | 100 – 200 Mbps |
| Home broadband (fast) | 500 – 1,000 Mbps |
| Wi-Fi 6 (local) | Up to 9,600 Mbps |
| 5G mobile | 100 – 2,000 Mbps |
Why actual download is slower than advertised:
ISP speeds are “up to” values shared across your neighborhood. Protocol overhead, server limits, Wi-Fi signal, and peak-hour congestion all reduce real-world throughput. A practical rule of thumb: expect 60–80% of your advertised speed for large downloads.
Common file size reference:
| File type | Typical size |
|---|---|
| MP3 song (4 min) | ~4 MB |
| HD movie (1080p) | 4 – 8 GB |
| 4K movie | 15 – 80 GB |
| PC game (modern) | 50 – 150 GB |
| Operating system ISO | 4 – 6 GB |
Decimal vs binary prefixes, the confusion explained
ISPs and storage manufacturers use SI decimal prefixes (1 MB = 1,000,000 bytes). Operating systems often use binary prefixes labeled the same way (1 MB = 1,048,576 bytes). This is why a 500 MB download from a website appears as about 476 MB in Windows Explorer once saved. The file isn’t smaller; Windows is just counting in 1024s while the website counts in 1000s. A 1 TB hard drive shows as about 931 GB in Windows for the same reason.
Real-world context for 2025
A 15 GB compressed 4K movie download takes:
- At 25 Mbps (FCC broadband minimum): about 80 minutes
- At 100 Mbps (common fiber tier): about 20 minutes
- At 1 Gbps (high-end fiber): under 2 minutes
- At 5G peak (100-300 Mbps real-world): 7-20 minutes
Mobile 5G advertised speeds of 1-4 Gbps are theoretical maximums; sustained throughput on a phone in a real city ranges from 100 to 300 Mbps.
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.