Worked examples
Times below use decimal gigabytes and include the 95% efficiency allowance. Without it, each time is about 5% shorter.
| Download | 50 Mbps | 300 Mbps | 1 Gbps |
|---|---|---|---|
| 1.5 GB mobile game update | 4.2 min | 42 s | 13 s |
| 20 GB 4K movie file | 56 min | 9.4 min | 2.8 min |
| 100 GB PC game | 4 h 41 min | 47 min | 14 min |
Why the real download often takes longer
Overhead. Every packet carries headers. On standard Ethernet, a full TCP packet delivers 1,460 bytes of data for every 1,538 bytes on the wire, about 94.9%. That is why a gigabit connection tops out at roughly 940 to 950 Mbps of actual data, and why the calculator's default allowance is 95%.
The other end. Game stores, cloud drives and file hosts often limit how fast one download can go, and they can be busier in the evening. If your speed test says 500 Mbps but a store shows 15 MB/s (120 Mbps), the bottleneck may be the server, not your line.
The disk. Games are downloaded, then decompressed and written. On slower drives, the "installing" phase can take longer than the download itself.
Wi-Fi. Use the speed you measured on the device that will do the download, in the room it sits in, not the speed on your plan.
GB or GiB?
Storage makers and most game stores use decimal gigabytes (1 GB = 1,000,000,000 bytes). Windows File Explorer uses binary units but labels them "GB", so a file Windows calls 100 GB is really 100 GiB, about 107.4 decimal GB. Pick GiB in the calculator when you copy a size from Windows.
Related
Measure your download speed · Convert Mbps to MB/s · Why results vary