Game Download Time Calculator

At the full 100 Mbps it takes 1 hour 6 minutes — that is the floor, the time you would get if every bit of the line carried game data. At 80% efficiency, a fair guess for a good home connection, it takes 1 hour 23 minutes, and at 60% it takes 1 hour 51 minutes. The calculator above shows all three as you move the efficiency setting.

Mbps is megabits per second and MB/s is megabytes per second, and a byte is 8 bits, so 1 MB/s equals 8 Mbps. Internet plans are sold in Mbps; game downloads are usually shown in MB/s. Valve’s support page puts it this way: “A byte is a group of 8 bits.” So a 100 Mbps plan tops out at 12.5 MB/s and a 1,000 Mbps plan at 125 MB/s. Use the unit toggle in the calculator if your speed test reports one and your game client the other.

At an advertised 100 Mbps you can move at most 45 GB per hour, and about 36 GB per hour at 80% efficiency. At 500 Mbps the ceiling is 225 GB per hour, and at 1,000 Mbps it is 450 GB per hour. Multiply by the hours you have to get how much game you can fit in.

Three things stack. Units: a speed test reports megabits and a game client often reports megabytes, so the same speed looks eight times smaller. Overhead: some of every packet is addressing and encryption, not game data. And the connection: Xbox Support lists Wi-Fi competition, other devices on your network, peak-hour ISP congestion and distance from the content server, and says the download speed “might not always match the top speeds that your ISP provides.” Neither Xbox nor Valve gives a percentage, which is why the efficiency setting here is yours to choose.

There is no published figure, so the presets are our own: 80% for a typical home setup, 90% for a quiet wired connection, 60% for evening peak or weak Wi-Fi. If you want a number based on your own line, start a download, read the speed your client shows, convert it to Mbps with the unit toggle, and divide by your plan’s speed. That ratio is your real efficiency.

By the definitions NIST publishes, 1 GB is 1,000,000,000 bytes and 1 GiB is 1,073,741,824 bytes, which is 7.4% more. This calculator uses GB (1,000,000,000 bytes) by default and lets you switch to GiB. Steam’s store pages and client do not say which one their “GB” means, so a large game can differ by that margin either way — on a 150 GB game, 11.1 GB.

Steam’s store page lists 150 GB of storage for Baldur’s Gate 3 (read 29 September 2026). If the download were that size, at 80% efficiency it would take 4 hours 10 minutes at 100 Mbps, 1 hour 23 minutes at 300 Mbps and 25 minutes at 1,000 Mbps. That storage figure is the space needed on disk, so the real download can be smaller; read the size Steam shows before you press install.

Not necessarily. The storage line on a Steam page is the disk space the game needs once installed, and the download that Steam shows in its own install prompt can be different, and later patches can change it again. Use the size in the client’s install dialog for the most accurate calculation, and the store-page figure only as a rough guide.

Work backwards from launch: take the realistic download time and add a margin, because a speed that holds for an hour may not hold overnight. The preload planner adds 25% by default. For example, a 150 GB game at 100 Mbps and 80% efficiency takes 4 hours 10 minutes; with a 25% margin, start at least 5 hours 12 minutes before unlock. Xbox Support also notes that ISP contention peaks on weekday evenings and weekends, and suggests overnight starts to avoid it.

The whole download counts, once, as data. A 150 GB game uses 15% of a 1,000 GB cap and 30% of a 500 GB cap, before anything else in the household streams. If the download is interrupted and restarted, some data may be fetched twice, so leave headroom. Enter your cap in the calculator to see the share for your own download.