📶 Bandwidth Calculator
Estimate how long a file will take to download or upload based on its size and your connection speed.
Transfer Details
Your Result
File sizes use the binary convention (1 KB = 1024 bytes). Real-world transfer speeds are often lower than the rated connection speed due to overhead and network conditions.
How the Bandwidth Calculator Works
Download time depends on file size (measured in bytes) and connection speed (measured in bits per second). Since 1 byte equals 8 bits, the calculator converts both values into bits before dividing to find the time in seconds.
Formula
Connection Speed (bits/sec) = Speed × unit multiplier
Download Time (seconds) = File Size (bits) ÷ Connection Speed (bits/sec)
Binary vs. Decimal Units
This calculator uses the binary convention where 1 KB = 1024 bytes, 1 MB = 1024 KB, and so on — matching how most operating systems report file sizes. Connection speeds (Kbps, Mbps, Gbps) use the decimal convention where 1 Mbps = 1,000,000 bits per second, which is the industry standard for ISPs.
Frequently Asked Questions
Why is my actual download slower than my rated internet speed?
Rated speeds are theoretical maximums. Actual speeds are affected by network congestion, server limits, Wi-Fi signal strength, and protocol overhead, so real transfers are often somewhat slower.
What's the difference between Mbps and MBps?
Mbps (megabits per second) measures connection speed, while MBps (megabytes per second) measures file size transfer. Since 1 byte = 8 bits, divide Mbps by 8 to get an approximate MBps transfer rate.
Does this calculator account for network overhead?
No, it calculates a theoretical minimum time based on the stated connection speed. Real-world downloads are typically a bit slower due to protocol overhead and network conditions.