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Download Time Calculator
Estimate how long a file, game or backup takes to download or upload at your connection speed. Mix units freely (MB, GB, GiB with Mbps or MB/s), add realistic overhead, or work out the speed you need to finish in a set time.
Calculate
%
Protocol overhead and real-world losses; 5–10% is typical, 0 for the theoretical time.
Enter your values to see the result.
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How to use the Download Time Calculator
- Enter the file size and choose its unit (for example 50 GB).
- Enter your connection speed, usually in Mbps as shown by a speed test.
- Set the overhead (10% is a realistic default, 0 for the theoretical best).
- Press Calculate time to see the estimated download time and the table of other speeds.
- Need a deadline? Switch to Speed needed and enter the time you have.
Download time formula
- Time (s) = file size in bits ÷ (speed in bits per second × (1 − overhead))
- File size in bits = bytes × 8 · 1 MB = 1,000,000 bytes · 1 MiB = 1,048,576 bytes
- 1 Mbps = 1,000,000 bits/s = 0.125 MB/s
- Speed needed = bits ÷ seconds available ÷ (1 − overhead)
Download time chart (no overhead)
| File size | 10 Mbps | 50 Mbps | 100 Mbps | 500 Mbps | 1 Gbps |
|---|---|---|---|---|---|
| 100 MB | 1 min 20 s | 16 s | 8 s | 1.6 s | 0.8 s |
| 1 GB | 13 min 20 s | 2 min 40 s | 1 min 20 s | 16 s | 8 s |
| 4 GB | 53 min 20 s | 10 min 40 s | 5 min 20 s | 1 min 4 s | 32 s |
| 50 GB | 11 h 6 min 40 s | 2 h 13 min 20 s | 1 h 6 min 40 s | 13 min 20 s | 6 min 40 s |
| 100 GB | 22 h 13 min 20 s | 4 h 26 min 40 s | 2 h 13 min 20 s | 26 min 40 s | 13 min 20 s |
| 1 TB | 9 d 6 h 13 min 20 s | 1 d 20 h 26 min 40 s | 22 h 13 min 20 s | 4 h 26 min 40 s | 2 h 13 min 20 s |
Add roughly 5–15% for real-world conditions. If a download is much slower than these figures, run a speed test and try a wired connection.
Frequently asked questions
How do I calculate download time?
Convert the file size to bits (bytes × 8) and divide by the speed in bits per second. For example, 50 GB = 400,000,000,000 bits; at 100 Mbps (100,000,000 bit/s) that is 4,000 seconds, about 1 hour 7 minutes, before overhead.
Why is my download slower than my internet speed?
Providers sell speeds in megabits per second, while files are measured in megabytes, so 100 Mbps is at most 12.5 MB/s. Protocol overhead, Wi-Fi interference, other devices on the network and the server's own limits reduce it further.
What is the difference between Mbps and MB/s?
Mbps is megabits per second and MB/s is megabytes per second. One byte is 8 bits, so divide Mbps by 8 to get MB/s: 300 Mbps ≈ 37.5 MB/s.
What is the difference between GB and GiB?
A gigabyte (GB) is 1,000,000,000 bytes; a gibibyte (GiB) is 1,073,741,824 bytes (2³⁰). Windows reports file sizes in binary units while labelling them GB, so a file Windows calls 50 GB is 50 GiB, about 53.7 GB.
How long does it take to download 100 GB?
At 100 Mbps it takes about 2 hours 13 minutes with no overhead, and about 2 hours 28 minutes with 10% overhead. At 1 Gbps it takes about 13 minutes 20 seconds without overhead.
Can I use this for upload time?
Yes. Enter your upload speed instead of the download speed. Upload speeds on many home connections are much lower than download speeds, so uploads usually take longer.
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