Technology

Download Time Calculator

Estimate how long a download takes for any file size and internet speed. Supports Mbps, Gbps and MB/s with a friendly ETA from this free download calculator.

Download Time Calculator

File size

Size unit

Internet speed

Speed unit

Method

How this calculator works

Time in seconds = file size in bits ÷ speed in bits per second. Size in bits = bytes × 8 (MB = 1e6 B, GB = 1e9 B, TB = 1e12 B); speed in bits/s uses Mbps = 1e6, Gbps = 1e9, and MB/s = 8e6.

Enter the file size and select its unit (MB, GB, or TB).
Enter your internet speed and choose Mbps, Gbps, or MB/s.
The tool converts size to bits and speed to bits per second.
Read the estimated download ETA in hours, minutes, and seconds, plus an adjusted real-world range.

Examples

Worked examples

Real numbers, end-to-end results.

1 GB at 100 Mbps

= 0:01:20

1 GB × 8e9 = 8,000,000,000 bits ÷ 100,000,000 bits/s = 80 s.

25 GB at 500 Mbps

= 0:06:40

25 GB × 8e9 = 2e11 bits ÷ 5e8 bits/s = 400 s.

4 GB at 20 MB/s

= 0:03:20

20 MB/s = 160,000,000 bits/s; 3.2e10 bits ÷ 1.6e8 = 200 s.

Use cases

When to use it

See how long a game, film, or OS update will take before starting it.
Decide whether to download now or overnight on a slower link.
Compare how much time a faster internet plan would actually save.
Plan large downloads around metered or capped data allowances.

FAQ

Frequently asked questions

How do I calculate download time?

Convert the file size to bits and the internet speed to bits per second, then divide: time in seconds = total bits ÷ bits per second. This tool does the conversion and formats the result as an ETA.

Why does my download take longer than the estimate?

The estimate is a theoretical best case. Real downloads lose 10–20% to TCP/IP overhead, server limits, congestion, and Wi-Fi conditions, so allow extra time compared to the calculated figure.

Is 100 Mbps fast for downloading?

100 Mbps delivers up to about 12.5 MB/s, so a 1 GB file takes roughly 80 seconds in ideal conditions. It is comfortable for HD streaming and typical downloads, though large game files still take several minutes.

What is the difference between Mbps and MB/s in downloads?

Internet speeds are advertised in megabits per second (Mbps), but download managers often show megabytes per second (MB/s). Divide Mbps by 8 to get MB/s, so 80 Mbps equals about 10 MB/s.

Does file size use decimal or binary units here?

This calculator uses decimal units, where 1 GB equals 1,000,000,000 bytes, matching how most download sizes and internet speeds are advertised.