How to use the download time calculator
Enter the file size and pick its unit, then your internet speed. The result is the time the download takes at that speed, allowing for the share of the line lost to network overhead (90% usable by default). Use the same calculator for uploads: enter your upload speed instead. If you don't know your speed, run our speed test first.
The formula
Time (s) = size (MB) × 8 ÷ (speed (Mbps) × efficiency)
The key step is multiplying by 8. File sizes are counted in bytes and internet speeds in bits, and one byte is eight bits. Forgetting this is why downloads seem to take eight times longer than expected.
Worked example: a 50 GB game is 50,000 MB, or 400,000 megabits. On a 100 Mbps line at 90% efficiency, 90 Mbps is usable, so the download takes 400,000 ÷ 90 = 4,444 seconds, about 1 hour 14 minutes.
How long common downloads take
| Download | Size | 25 Mbps | 100 Mbps | 500 Mbps | 1 Gbps |
|---|---|---|---|---|---|
| Song (MP3) | 5 MB | 2 s | 0.4 s | 0.1 s | 0.04 s |
| Phone app | 200 MB | 71 s | 18 s | 4 s | 2 s |
| HD movie | 4 GB | 24 min | 6 min | 71 s | 36 s |
| 4K movie | 20 GB | 2 h | 30 min | 6 min | 3 min |
| Large game | 100 GB | 9.9 h | 2.5 h | 30 min | 15 min |
Times assume 90% efficiency. Real downloads can be slower when the server is busy, because the speed is limited by the slowest point between you and the server, not only by your plan.
Why downloads can be slower than this
- The server. Game stores and cloud services may limit how fast each user can download, especially on launch days.
- The disk. Games are unpacked while they download; on an old hard drive or console, that can be the bottleneck above about 300 Mbps.
- Wi-Fi and sharing. Other people streaming, or a weak Wi-Fi signal, reduce your share of the line. Lower the efficiency setting to model this.
- GB versus GiB. Windows shows sizes in binary units (1 GiB = 1,073.7 MB) but labels them "GB". A file shown as 50 GB in Windows is really 53.7 GB in decimal units.
Frequently asked questions
How long does it take to download 1 GB?
On a 100 Mbps connection, 1 GB takes about 1.5 minutes (89 seconds at 90% efficiency). On 25 Mbps it takes about 6 minutes, and on a 1 Gbps line about 9 seconds.
How do I calculate download time?
Convert the file size to megabits by multiplying megabytes by 8, then divide by your usable speed in Mbps. For example, 4,000 MB × 8 = 32,000 megabits; at 90 Mbps that's 356 seconds, about 6 minutes.
Why is my download slower than my internet speed?
Network overhead uses about 5–10% of the line, the server may limit each user's speed, and Wi-Fi or other devices take a share. Also check the units: a download manager showing 12 MB/s on a 100 Mbps plan is running at full speed.
How long does it take to upload a file?
Use the same calculation with your upload speed, which is often much lower than download on cable and DSL. Uploading a 10 GB video at 10 Mbps takes about 2.5 hours, compared with 15 minutes at 100 Mbps.
Download times are estimates. Actual times depend on the server, your device, Wi-Fi and other traffic on your network.