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Download Time Calculator

Work out how long a file will take to download at your internet speed, with megabits and megabytes explained.

Rules last checked 25 October 2026Every step shown

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Download time

34 min 49 s

Speed in MB/s
2.25 MB/s

A 4.7 GB file on a 20 Mbps connection takes about 34 min 49 s.

How it's worked out

  1. Size in megabits4.7 GB × 8 bits a byte37,600 Mb
  2. Usable speed20 Mbps − 10%18 Mbps
  3. Time37,600 ÷ 1834 min 49 s
  • Internet speeds are sold in megabits (Mbps); files are measured in megabytes (MB). One byte is 8 bits, so 20 Mbps downloads at about 2.5 MB/s at best.

The formula

Time = file size in bits ÷ (speed in bits per second × (1 − slowdown))

Worked example

4.7 GB is 37,600 megabits. At 20 Mbps less 10%, that's 18 Mbps, so 37,600 ÷ 18 = 2,089 seconds: 34 minutes 49 seconds.

Questions people ask

Why is my download slower than my internet speed?

Internet speeds are sold in megabits per second (Mbps), but downloads show megabytes per second (MB/s). One byte is 8 bits, so 20 Mbps is at most 2.5 MB/s.

How long does a 4.7 GB file take on 20 Mbps?

About 35 minutes, allowing 10% for real-world slowdown.

How do I convert Mbps to MB/s?

Divide by 8.

Formula and rules last checked 25 October 2026Written and tested by the CalculatorDex teamReport a problem