OneTaskBy Tim King · Updated
Download Time Calculator
How Long a File Takes at Your Speed
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How the Download Time Calculator works
This download time calculator tells you how long a file will take to arrive. Enter the size of the game, film or backup, your connection speed and an allowance for overhead, and it shows the realistic time, the best case at full line speed and the effective speed in MB/s. It works for uploads too.
Connection speeds are sold in megabits per second while file sizes are measured in bytes, so the sum needs a factor of 8 that is easy to forget. On top of that, a line never delivers its full rated speed as file data. Some capacity goes on packet headers, encryption and resent packets, which is what the overhead allowance covers.
How the download time calculator works
The formula is time = size in bits ÷ effective speed in bits per second. The size is turned into bytes using the unit you chose, then multiplied by 8. The effective speed is the line speed × (1 − overhead ÷ 100). The tool shows the result with overhead and without it, so you can see the range.
First example. A 100 GB game on a 67 Mbps line is 800,000 megabits. At full speed that is 11,940 seconds, or 3 h 19 min. With 10% overhead the line delivers 60.3 Mbps, about 7.54 MB/s, and the download takes 3 h 41 min.
Second example. A 4 GiB disk image is 4,294,967,296 bytes. On a 500 Mbps connection with 10% overhead the effective speed is 56.25 MB/s, and the file arrives in 1 min 16 s.
How many minutes per gigabyte? At 100 Mbps a gigabyte takes 80 seconds at full speed; at 1 Gbps, 8 seconds. Halve the speed and the time doubles.
Download time at full line speed for 1 GB, 10 GB, 50 GB and 100 GB
| Speed | 1 GB | 10 GB | 50 GB | 100 GB |
|---|---|---|---|---|
| 1 Mbps | 2 h 13 min | 22 h 13 min | 4 d 15 h 6 min | 9 d 6 h 13 min |
| 2 Mbps | 1 h 6 min | 11 h 6 min | 2 d 7 h 33 min | 4 d 15 h 6 min |
| 5 Mbps | 26 min 40 s | 4 h 26 min | 22 h 13 min | 1 d 20 h 26 min |
| 10 Mbps | 13 min 20 s | 2 h 13 min | 11 h 6 min | 22 h 13 min |
| 16 Mbps | 8 min 20 s | 1 h 23 min | 6 h 56 min | 13 h 53 min |
| 20 Mbps | 6 min 40 s | 1 h 6 min | 5 h 33 min | 11 h 6 min |
| 25 Mbps | 5 min 20 s | 53 min 20 s | 4 h 26 min | 8 h 53 min |
| 30 Mbps | 4 min 27 s | 44 min 27 s | 3 h 42 min | 7 h 24 min |
| 40 Mbps | 3 min 20 s | 33 min 20 s | 2 h 46 min | 5 h 33 min |
| 50 Mbps | 2 min 40 s | 26 min 40 s | 2 h 13 min | 4 h 26 min |
| 67 Mbps | 1 min 59 s | 19 min 54 s | 1 h 39 min | 3 h 19 min |
| 75 Mbps | 1 min 47 s | 17 min 47 s | 1 h 28 min | 2 h 57 min |
| 80 Mbps | 1 min 40 s | 16 min 40 s | 1 h 23 min | 2 h 46 min |
| 100 Mbps | 1 min 20 s | 13 min 20 s | 1 h 6 min | 2 h 13 min |
| 150 Mbps | 53.3 s | 8 min 53 s | 44 min 27 s | 1 h 28 min |
| 200 Mbps | 40 s | 6 min 40 s | 33 min 20 s | 1 h 6 min |
| 300 Mbps | 26.7 s | 4 min 27 s | 22 min 13 s | 44 min 27 s |
| 500 Mbps | 16 s | 2 min 40 s | 13 min 20 s | 26 min 40 s |
| 900 Mbps | 8.9 s | 1 min 29 s | 7 min 24 s | 14 min 49 s |
| 1,000 Mbps | 8 s | 1 min 20 s | 6 min 40 s | 13 min 20 s |
| 2,000 Mbps | 4 s | 40 s | 3 min 20 s | 6 min 40 s |
| 10,000 Mbps | 0.8 s | 8 s | 40 s | 1 min 20 s |
Tips and pitfalls
- Test your real speed. Use a speed test on the device doing the download, not the package speed. Wi-Fi often delivers half of what the line can.
- The server sets a ceiling. Game stores and cloud services may cap each download, so a gigabit line can still wait on a slow server.
- Uploads are usually slower. Most broadband is asymmetric; enter your upload speed to time a backup or a video upload.
- Use MB/s for a running download. If your browser shows 8 MB/s, choose MB/s as the unit and set the overhead to 0, since that figure is already file data.
FAQ
How long does it take to download 100 GB?
About 2 h 13 min at 100 Mbps at full speed, or around 2.5 hours with normal overhead. At 1 Gbps it takes about 13 to 15 minutes, and at 30 Mbps roughly 7.5 to 8 hours.
Why is my download slower than my broadband speed?
Your provider quotes megabits per second and download tools show megabytes per second, which is eight times smaller. Overhead takes another 5% to 10%, and Wi-Fi, busy networks or the server can slow things further.
What overhead should I use?
Ten percent suits most wired connections. Use 15% to 25% for Wi-Fi or a busy shared line, and 0% when you enter a speed you read from a download already in progress, as that is file data already.
How do I work out upload time?
Enter the file size and your upload speed instead of your download speed. Many broadband plans upload at a fifth or a tenth of the download speed, so large uploads take much longer than downloads.
Does a GiB take longer than a GB?
Yes, slightly. A GiB is 1,073,741,824 bytes, about 7.4% more than a GB, so it takes 7.4% longer at the same speed. Choose GiB when the size came from Windows or a Linux tool.
See also: all Unit Converters tools, Everyday Maths, Loans & Savings, Dates & Time, Health, Home & DIY, Education, Science, Creative, Garden & Farm, Gaming & PC, Work & Business, Fun, Maps & GPS, DIY & Building, Cost Estimators, Sport & Clubs.
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