This download time calculator shows how long it takes to download or upload a file at a given internet speed. It converts between bytes and bits, allows for network overhead, and compares times at common broadband speeds.
Download time formula
Time (seconds) = file size in bits ÷ effective speed in bits per second
File sizes are measured in bytes and internet speeds in bits, and 1 byte = 8 bits. That is why a 100 Mbps connection downloads about 12.5 megabytes per second at best, and less in practice.
Worked example
A 50 GB game on a 300 Mbps connection is 400 gigabits. Allowing 10% for overhead, the effective speed is 270 Mbps, so the download takes about 24 minutes 41 seconds.
Common speeds compared (1 GB file, 10% overhead)
| Speed | Time |
|---|---|
| 25 Mbps | 5 minutes 56 seconds |
| 100 Mbps | 1 minute 29 seconds |
| 300 Mbps | 30 seconds |
| 500 Mbps | 18 seconds |
| 1 Gbps | 9 seconds |
| 2 Gbps | 4 seconds |
Why downloads are slower than advertised
- Wi-Fi signal strength and older routers.
- The server or game store limiting its upload speed.
- Other devices on your network using bandwidth.
- Upload speeds on many cable and DSL plans are much lower than download speeds.
Frequently asked questions
What is the difference between Mbps and MB/s?
Mbps is megabits per second; MB/s is megabytes per second. Divide Mbps by 8 to get MB/s.
What is a GiB?
A gibibyte is 1,073,741,824 bytes (2³⁰). Some operating systems show sizes in GiB but label them GB, which is why sizes can look different.
How much overhead should I allow?
About 5% to 10% covers network protocol overhead. Use more if your Wi-Fi is weak or the network is busy.
Does this work for uploads?
Yes. Enter your upload speed instead of your download speed.
Related calculators
Last reviewed: October 2026. For information only; results are estimates; check important figures with a professional.