ToolCalcu

Download Time Calculator

Enter a file size and your connection speed to estimate how long the download will take. Bits and bytes are handled for you.

File and connection

Real downloads rarely reach the advertised speed. Enter a percentage such as 10 to model that loss, or leave it empty.

Result

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Estimated download time
13 min 20 sec
Total time
800 sec
Effective speed
50 Mbps
Effective speed in MB/s
6.25 MB/s
File size in bytes
5,000,000,000 B

How download time is calculated

Internet speeds are quoted in bits per second, while file sizes are quoted in bytes, and one byte is eight bits. To compare them, the file size is converted to bits and divided by the speed.

This calculator uses decimal units: 1 MB is 1,000,000 bytes and 1 Mbps is 1,000,000 bits per second. Some operating systems show sizes in binary units (MiB, GiB), which are about 5% to 7% larger, so their downloads take slightly longer than shown here.

Formulas used

Size in bits = File size (bytes) × 8
Effective speed = Speed × (1 − Overhead % ÷ 100)
Time (seconds) = Size in bits ÷ Effective speed (bits per second)

Worked example

A 5 GB file on a 50 Mbps connection with no overhead:

  1. Size in bits: 5 × 1,000,000,000 bytes × 8 = 40,000,000,000 bits
  2. Speed in bits per second: 50 × 1,000,000 = 50,000,000
  3. Time: 40,000,000,000 ÷ 50,000,000 = 800 seconds

5 GB at 50 Mbps takes 13 min 20 sec.

Assumptions and limits

  • The speed is constant during the whole download.
  • Overhead can be 0% to 90%; leave it empty to ignore it.
  • Speeds quoted as MB/s are megabytes per second, eight times the same number in Mbps.

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