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Bandwidth Calculator

Estimate how long a file transfer or download will take, based on file size and connection speed.

About this calculator

Estimate how long a file transfer or download will take, given the file size and your connection speed.

Internet speeds are usually advertised in megabits per second (Mbps), but file sizes are measured in megabytes (MB) — and there are 8 bits in a byte, so a "100 Mbps" connection tops out around 12.5 MB/s in practice, before accounting for overhead. This calculator converts both inputs to a common unit before dividing, so you don't have to do the bits-to-bytes conversion yourself.

How to use

  1. Enter the file or data size and select its unit (KB, MB, GB, or TB).
  2. Enter your connection speed and select its unit (Kbps, Mbps, or Gbps).
  3. Press Calculate to see the estimated transfer time.

Tips

  • Real-world transfer speeds are usually somewhat lower than the advertised connection speed due to network overhead — treat this as a best-case estimate.

Formula

Time = File Size (bits) ÷ Connection Speed (bits per second)