Internet Download Time Calculator

Direct answer

Convert decimal gigabytes to megabits, then divide by the entered download speed. The Federal Communications Commission distinguishes download and upload performance and notes that measured broadband data comes from user-initiated tests; use a current measured download speed when you need an estimate for your connection.

Variables and formula

• File size: decimal gigabytes shown for the file.
• Download speed: megabits per second (Mbps).

Download minutes = File size GB × 8,000 / Download Mbps / 60

Reproducible example

For a 5 GB file at 100 Mbps, the file is 5 × 8,000 = 40,000 megabits. The ideal transfer time is 40,000 / 100 = 400 seconds, or about 6.67 minutes.

Interpretation

This is an ideal constant-speed estimate. A result of 6.67 minutes means the entered file and speed have that mathematical relationship, not that a real transfer is guaranteed to finish at that time.

Assumptions and limitations

• GB and Mbps use decimal multipliers.
• The speed is constant for the entire transfer.
• Protocol overhead, Wi-Fi conditions, server limits and other traffic are excluded.

Common mistakes

• Confusing megabits (Mb) with megabytes (MB).
• Using upload speed for a download.
• Treating an advertised plan speed as a measured transfer speed.

Assumptions

• GB is treated as decimal gigabytes and Mbps as decimal megabits per second.
• The speed remains constant and protocol overhead, contention and device limits are excluded.

Sources and methodology

CalcMotive publishes the formula and assumptions so you can decide whether the estimate fits your use case. See our methodology standards.

• International Broadband Data Report 2024; Federal Communications Commission; accessed Jul 30, 2026