Download Time Calculator

Because internet plans are almost always advertised in megabits per second (Mbps), not megabytes per second (MB/s), and there are 8 bits in a byte. A 100 Mbps connection tops out around 12.5 MB/s in practice, not 100 MB/s -- an 8x difference that catches people off guard constantly. This calculator's Effective Speed output is shown in Mbps to match how your plan is advertised, but every internal calculation converts to a common bit-based unit first specifically to avoid this mix-up.

Because file sizes and network speeds are conventionally quoted in different unit families that don't share a common multiplier by default -- a 500 GB game download over a 50 Mbps connection mixes gigabytes with megabits, and getting the conversion wrong by using the wrong unit produces a wildly incorrect time estimate (potentially off by a factor of 1,000 or more if GB is mistaken for Mb). Selecting both units explicitly lets this calculator normalize everything to megabits internally before doing the actual division.

It's a theoretical best case based on your entered file size and rated connection speed alone. Real downloads are also slowed by the server's own upload capacity, network congestion between you and the server, Wi-Fi signal quality if you're not on a wired connection, and protocol overhead -- none of which this calculator accounts for. Actual download times are commonly somewhat longer than this estimate, especially for very large files where any brief slowdown accumulates over the whole transfer.

Because 4.7 GB is the standard capacity of a single-layer DVD, a widely recognized reference file size that makes the resulting download time easy to sanity-check against intuition -- most people have some sense of how long "a DVD's worth of data" should take on a given connection. It's a starting example you're meant to replace with your own file size, not a suggestion about what you're downloading.