Estimates, not promises

DownloadTime computes estimates. The math is exact — time really is bits divided by bits-per-second — but its inputs are approximations of a noisy physical system. Your actual transfer time depends on protocol overhead, Wi-Fi conditions, the far server’s capacity, peering, congestion at your exchange and a dozen other factors no calculator can see. Treat results as the honest middle of a range, not a guarantee.

About the numbers on this site

• Figures like “85–95% typical efficiency” or the GB-per-hour streaming table are typical values drawn from public documentation and common measurement, not specifications. Bitrates, app behavior and ISP plans change; when precision matters, measure your own case — the reverse panels on the calculator exist for exactly that.
• Unit conventions vary by vendor and OS. We’ve made the decimal/binary distinction explicit rather than silently choosing for you, but “what Windows calls a GB” may differ from what your NAS calls a GB.
• Nothing here is engineering, purchasing or contractual advice. Don’t provision an event’s bandwidth, sign a data plan, or promise a client a transfer deadline based solely on this site’s output — measure the real link first.

Advertising and independence

This site is funded by display advertising (Google AdSense). Ads are sold by the network, not chosen by us per-page, and they have no influence on the calculator’s math or the articles’ conclusions — a result doesn’t change because of who’s advertising beside it.

Liability

The site and its tools are provided “as is” without warranty of any kind. We work to keep the math right and the content current; if you find we got something wrong, the contact page is the fastest way to get it fixed.