Why is the real download slower than the estimate?

Real-world throughput is reduced by protocol overhead, network congestion, server limits and Wi-Fi loss. Use the overhead field (commonly 10–20%) for a closer estimate, but actual time still varies — this tool gives an approximation, not a guarantee.

Is my file or speed data sent anywhere?

No. The calculator is privacy-first and runs entirely in your browser — nothing you enter is uploaded or stored anywhere.

Download Time Calculator

Q: How is download time calculated?

Download time equals file size divided by connection speed, after converting both to bits. The formula is: time (seconds) = file size in bits / speed in bits per second. Since 1 byte = 8 bits, a 1 GB file is 8 billion bits, so on a 100 Mbit/s line it takes about 80 seconds (plus overhead).

Download Time Calculator

Estimate how long a file will take to download from its size and your connection speed. The maths is straightforward once units line up: file size is measured in bytes (1 byte = 8 bits), while connection speed is advertised in bits per second (Mbit/s). Convert both to bits, then divide:

time (seconds) = file size in bits ÷ speed in bits per second

So a 1 GB file (8 billion bits) on a 100 Mbit/s line needs about 80 seconds in theory. Real downloads are slower because of protocol overhead and congestion, so add 10–20% overhead for a realistic figure. Everything is calculated locally in your browser — nothing is sent anywhere.