Bandwidth Calculator
Estimate how long a download or transfer will take based on file size and your connection speed.
What this calculator does
Internet speeds are usually advertised in megabits per second (Mbps), but file sizes are usually shown in megabytes or gigabytes (MB/GB), which trips people up when estimating download times. This calculator converts both to a common unit and estimates real transfer time.
The formula
File size is converted to megabits by converting to megabytes first, then multiplying by 8 (since there are 8 bits in a byte). Connection speed is converted to Mbps if given in another unit. Real-world networks rarely achieve their full rated speed due to protocol overhead, other network traffic, and connection quality, so an overhead percentage is subtracted to get a more realistic effective speed. Dividing file size in megabits by effective speed in Mbps gives the estimated transfer time in seconds.
Actual transfer times vary with network congestion, server-side limits, and Wi-Fi conditions, so treat this as a general estimate.