GENERAL / TRANSFER TIME
Download Speed Calculator
Estimate how long a file will take to download from its size, connection speed, and a visible overhead assumption.
Set transfer inputs
Choose the units shown by your file and connection.
Download estimate
Your download estimate will appear here
Enter file size and connection speed, then calculate.
Why the estimate differs from a speed-test headline
Download time in seconds = file size in bytes × 8 ÷ effective bits per second. Effective speed = connection speed × (1 − overhead ÷ 100). Time is rounded to the nearest second, with sub-second transfers shown as less than one second.
Bits versus bytes
Internet plans commonly use Mbps, while operating systems often show MB/s. Dividing Mbps by 8 gives the pre-overhead MB/s equivalent.
Model limitations
The calculation does not simulate congestion, latency, server behavior, throttling, or changing connection speed. Treat it as an ETA estimate.
Frequently Asked Questions
What is the difference between Mbps and MB/s?
Mbps means megabits per second, while MB/s means megabytes per second. There are 8 bits in one byte, so 8 Mbps equals 1 MB/s before overhead.
What does protocol overhead represent?
It is a simple percentage reduction for protocol, network, or transfer inefficiency. The actual impact depends on the connection and service.
How are GB, TB, GiB, and TiB converted?
GB and TB use decimal units: 1 GB = 1,000,000,000 bytes and 1 TB = 1,000 GB. GiB and TiB use binary units: 1 GiB = 1,073,741,824 bytes and 1 TiB = 1,024 GiB.
Why might the real download take longer?
Server load, Wi-Fi conditions, congestion, latency, throttling, and other traffic can make the real transfer slower than the estimate.
Does the calculator store my file or speed?
No. The calculation runs in your browser and does not upload the file or connection details.