Network / Transfers
Download Time Calculator: File Size and Connection Speed
Work out how long a download or upload takes from the file size and connection speed, allowing for protocol overhead, compare common connection speeds, and find the speed you need to finish within a given time.
Download Time Calculator: File Size and Connection Speed: Time = size in bits ÷ the usable speed. A 50 GB game is 400,000 megabits; at 100 Mbit/s with 10% lost to overhead, 90 Mbit/s remain, so it takes 4,444 seconds, 1 hour 14 minutes. Finishing within an hour would need about 123 Mbit/s. Runs 100% locally in your browser with zero server file uploads.
- Category
- Web tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
| Connection | Time |
|---|---|
| 10 Mbit/s | 12 h 20 min 44 s |
| 50 Mbit/s | 2 h 28 min 9 s |
| 100 Mbit/s | 1 h 14 min 4 s |
| 300 Mbit/s | 24 min 41 s |
| 500 Mbit/s | 14 min 49 s |
| 1000 Mbit/s | 7 min 24 s |
Connection speeds are sold in megabits per second and file sizes are shown in bytes, and there are 8 bits in a byte, so 100 Mbit/s moves at most 12.5 MB a second. Protocol overhead, Wi-Fi, and a busy server take part of the line; 10% is a fair allowance on a good connection. KB, MB, and GB are powers of 1,000; KiB, MiB, and GiB, which Windows shows as KB, MB, and GB, are powers of 1,024.
Typical times for 1 GB
At 10 Mbit/s about 15 minutes, at 100 Mbit/s about 1.5 minutes, and at 1 Gbit/s about 9 seconds, with 10% overhead.
Converting sizes
To switch between MB, MiB, GB, and other units, use the file size converter.
How to use it
- Enter the file size and choose its unit, such as GB or GiB.
- Enter your connection speed, usually in Mbit/s, and the overhead.
- Read the time, or add a deadline to see the speed needed.
Privacy & limitations
Everything is calculated in your browser.
Related tools
Frequently asked questions
Why is my download slower than my plan's speed?
Plans quote the maximum line speed in megabits; Wi-Fi, other devices, the server's own limits, and protocol overhead all take a share, and 8 bits make a byte, so 100 Mbit/s shows as about 11 to 12 MB/s in a download window.
What is the difference between GB and GiB?
A GB is 1,000,000,000 bytes and a GiB is 1,073,741,824. Windows reports sizes in GiB but labels them GB, so a file Windows calls 50 GB is about 53.7 GB.
Does upload work the same way?
Yes, but use your upload speed, which on many home connections is much lower than the download speed.
Free tool · runs in your browser · no account required