Calculate how long it takes to download a file from its size and your connection speed, with a realistic estimate. Enter your values; the result updates as you type, with the method shown below.
About this calculator
How long will a download or an upload take? This calculator converts a file size and a connection speed into a time, with a realistic estimate at 80% of the advertised speed.
Enter the file size (MB, GB or TB) and the connection speed in Mbit/s.
When to use it
- Planning a big game or system update.
- Uploading backups or videos.
- Comparing internet plans.
- Estimating a cloud migration.
How to read the result
Speeds are in bits, file sizes in bytes: 1 byte = 8 bits. 4 GB at 100 Mbit/s takes about 5 min 20 s in theory, more in practice.
Wi-Fi, server limits and other devices often reduce real speed.
Mistakes to avoid
- Confusing Mbit/s with MB/s.
- Expecting the advertised speed in practice.
- Using upload speed for a download.
Formula
Time = size × 8 / speed
Worked example
4 GB at 100 Mbit/s: 5 min 20 s (about 6 min 40 s in practice).
Frequently asked questions
Why is it slower in practice?
Protocol overhead and Wi-Fi reduce the real speed.
MB or Mb?
Files are in bytes (MB), connections in bits (Mbit/s): 1 byte = 8 bits.
Why divide by 8?
Speeds are in bits and file sizes in bytes.
Why 80%?
It accounts for protocol overhead and typical losses.
Upload or download?
Use the speed of the direction you need.
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Results are estimates for information only. Check important figures with a professional.