Bits vs bytes handled for you. 1000-based units.
Download Time Calculator
Enter a file size and your connection speed to find out how long the download should take. The comparison table shows the same file at 10, 50, 100 and 500 Mbps, so you can see what a faster plan would buy you.
The formula
First convert the file size to bits: bits = size x 8 x 1,000 to the power n, where n is 1 for KB, 2 for MB, 3 for GB and 4 for TB. Then divide by the connection speed in bits per second: seconds = bits / (speed x 1,000 to the power m), where m is 1 for Kbps, 2 for Mbps and 3 for Gbps.
Worked example
A 1 GB file is 1 x 8 x 1,000^3 = 8,000,000,000 bits. On a 100 Mbps connection (100,000,000 bits per second), that is 8,000,000,000 / 100,000,000 = 80 seconds.
Why real downloads are slower
The formula gives the theoretical minimum. In practice, protocol overhead eats a few percent, networks get congested at peak times, the server may limit your speed, and Wi-Fi rarely delivers the full plan speed to your device. Expect roughly 80 to 90% of the advertised speed on a good day.
Bits vs bytes
There are 8 bits in a byte. File sizes use bytes (KB, MB, GB, capital B) while connection speeds use bits (Kbps, Mbps, Gbps, lowercase b). A 100 Mbps plan moves 12.5 megabytes per second, not 100. Mixing them up is the most common download-time mistake.
Planning estimate only. Results use the list prices shown and may differ from your actual bill. Terms
Frequently asked questions
Why is my download slower than my internet plan?
Plans advertise the maximum speed to your home, not what reaches your device. Wi-Fi losses, network congestion, protocol overhead and the server's own limits all shave some off. A wired connection and off-peak hours get you closest to the advertised number.
What is the difference between MB and Mb?
MB is megabytes (file sizes), Mb is megabits (speeds), and 1 byte = 8 bits. A 100 Mbps connection downloads at 12.5 MB per second. Always check the capitalisation before doing the math.
How long does a 50 GB game take to download?
At 100 Mbps, about 1 hour 7 minutes (4,000 seconds). At 500 Mbps, about 13 minutes. Enter 50 GB in the calculator to see the time for your exact speed.
Does upload speed matter for downloads?
No. Downloads use your download speed only. Upload speed matters when you send files, back up photos, livestream or video call.
Why do providers use 1000 instead of 1024?
Telecom standards define kilo as 1,000, so a 100 Mbps plan is 100,000,000 bits per second. Operating systems historically used 1,024, which is why a drive or download can look slightly smaller than advertised. This calculator follows the provider convention: 1,000.