Bandwidth & Download Time Calculator

Work out how long a file takes to download at any speed, or how much monthly bandwidth a website needs.

How long will my download take?

Enter a file size (KB to TB) and a connection speed (kbit/s to Gbit/s) to get the download time, with a realistic estimate including network overhead and a table for 3G, 4G, fibre and 5G. Switch to website mode to estimate monthly bandwidth from page views and page size.

Bits vs bytes

Internet speeds are in megabits per second (Mbps); file sizes in megabytes (MB). One byte = 8 bits, so a 100 Mbps connection downloads about 12 MB per second at best.

Website bandwidth

Monthly bandwidth ≈ page views × average page size × a safety factor for bots and repeat loads. Caching, compression and a CDN can cut it dramatically.

Frequently asked questions

Why is my real download slower?

Protocol overhead, Wi-Fi quality and the server’s speed all reduce throughput.

Does it use binary units?

Sizes use 1 MB = 1,024 KB; speeds use decimal megabits as ISPs do.

Is it free?

Yes.