Download Time Calculator
Enter a file size and your connection speed to see how long the transfer should take.
Bits and bytes handled
Plans are sold in megabits (Mbps); files are measured in megabytes (MB). We convert between the two for you.
An ideal estimate
The result assumes you reach your full rated speed. Real transfers run a little slower because of network overhead.
How long will my download take?
File size meets connection speed
A download takes as long as it takes to push every bit of the file through your connection. So the time depends on just two things: how big the file is, and how fast your link moves data. A 1 GB game update over a 100 Mbps line is a very different wait from the same file over a 10 Mbps connection.
Enter the file size, pick its unit, then enter your connection speed and its unit to see the estimated download time.
The file size is converted into bits, the speed into bits per second, and one is divided by the other.
Time = (file size in bits) ÷ (speed in bits per second)The catch is the difference between bits and bytes. Internet plans are advertised in megabits per second (Mbps), but files are measured in megabytes (MB), and one byte is eight bits. So 100 Mbps is not 100 MB per second — it is only 12.5 MB per second, because you divide by 8. Getting that factor of 8 right is the single most common mistake people make when estimating download times, and it is exactly the step this calculator does for you.
Suppose you want to download a 1 GB file on a 100 Mbps connection.
Convert the file to bits
1 GB = 1,000,000,000 bytes × 8 = 8,000,000,000 bits.
Convert the speed to bits per second
100 Mbps = 100,000,000 bits per second.
Divide
8,000,000,000 ÷ 100,000,000 = 80 seconds, or about 1.33 minutes.
The biggest thing to watch is the unit you chose for speed. Mbps (megabits) is the figure on almost every broadband plan; MB/s (megabytes) is what a download manager usually displays, and it is eight times larger for the same connection. If your estimate looks eight times too long or too short, you have probably mixed up the two. Beyond that, treat the result as a best case: real speeds are routinely lower than the rated plan because of shared lines, Wi-Fi, distance to the server, and the protocol overhead that wraps every file in extra packets. A download that the calculator puts at 80 seconds might realistically take 90 to 110.
The arithmetic is exact, but a download is more than arithmetic.
An ideal-speed estimate
This calculator assumes a steady connection running at exactly its rated speed, with no overhead, latency, or congestion. In practice, TCP/IP overhead, Wi-Fi signal, a busy server, or other devices on your network all slow things down, so a real download usually takes somewhat longer than the figure shown. Use the result as a planning estimate, not a guarantee.