Download Time Calculator
Estimate how long a file takes to download from its size and your connection speed, with bits and bytes sorted out.
Note: 1 byte = 8 bits, so a 50 Mbps line moves about 6.25 MB every second. Real speeds run lower than the advertised rate once you factor in overhead.
How it works
The math is simple once the units line up: time equals file size divided by speed. The catch is that connection speeds are quoted in megabits per second (Mbps) while file sizes are in megabytes (MB), and there are eight bits in a byte.
So a 50 Mbps line actually moves about 6.25 MB every second. A 100 MB file over that connection takes 100 divided by 6.25, which is 16 seconds. This tool converts Mbps to MB/s for you and then does the division.
Remember that advertised speeds are a ceiling, not a promise. Wi-Fi interference, server limits, and protocol overhead all shave off real-world throughput, so treat the answer as a best case and expect a little longer.
Frequently asked questions
Why is my real download slower than this says?
The calculator assumes you hit your full advertised speed the whole time. In practice you rarely do — the server, your Wi-Fi, and network overhead all cost throughput, so add a margin.
What's the difference between Mbps and MB/s?
Mbps is megabits per second, the way internet speeds are sold. MB/s is megabytes per second, matching file sizes. One byte is eight bits, so divide Mbps by eight to get MB/s.
How do I calculate download time by hand?
Convert your speed to MB/s (Mbps ÷ 8), then divide the file size in MB by that number. For example, 1 GB is 1024 MB, and at 100 Mbps (12.5 MB/s) that's about 82 seconds.