Download Time Calculator — How Long Will This Download Take?
A download time calculator divides a file's size by your connection speed to estimate how long the transfer will take — the number you want before starting a 60 GB game download at 11 pm.
Quick answer: Time = file size (bits) ÷ speed (bits per second). On a 100 Mbps connection, 10 GB takes about 13 minutes 20 seconds at full line rate, or roughly 15 minutes in practice after accounting for protocol overhead.
Estimate how long a download will take on your connection — enter the file size and your real-world speed.
| File size | Time |
|---|---|
| 700 MB (CD) | 15 h 33 min 20 s |
| 4.7 GB (DVD) | 6 min 16 s |
| 25 GB (Blu-ray) | 33 min 20 s |
| 50 GB | 1 h 6 min 40 s |
| 100 GB | 2 h 13 min 20 s |
| 1 TB | 22 h 13 min 20 s |
ISPs sell megabits (Mbps), browsers and file managers show megabytes (MB/s). One byte is eight bits, so a 100 Mbps line tops out around 12.5 MB/s — and that is before protocol overhead.
| Formula | seconds = GB × 8,000 ÷ Mbps (decimal GB) |
|---|---|
| 100 Mbps | 10 GB ≈ 13 min · 50 GB ≈ 67 min · 100 GB ≈ 2 h 13 min |
| 50 Mbps | 10 GB ≈ 27 min · 50 GB ≈ 2 h 13 min |
| 1 Gbps | 10 GB ≈ 80 s · 100 GB ≈ 13 min |
| Reality factor | Plan on 85–95% of line rate; servers and Wi-Fi steal the rest |
Why a 10 GB download never takes exactly 13 minutes
The line rate is a ceiling: TCP headers, TLS handshakes, the store's CDN throttling and disk writes all take a bite. Wired connections typically sustain 92–96% of the plan speed, Wi-Fi 6 at close range 70–85%, and older Wi-Fi or powerline adapters can drop under 50%. The calculator shows the clean number and the 90% figure so you can choose which to plan around.
Big downloads: games, updates and ISO images
Modern game installs are the main reason people search for this: a 120 GB download on a 100 Mbps line is 2 hours 40 minutes at line rate — often an overnight job. Steam and console stores usually saturate the connection, but they also download compressed assets and then unpack them, so budget another 20–40% of the transfer time for installation on slower drives.
Getting the fastest realistic speed
Use Ethernet rather than Wi-Fi for large transfers, check nothing else is streaming, and test with a speed test before trusting the plan figure. If the download is slower than 80% of the plan speed on a wired connection, the bottleneck is usually the server or the router's NAT table, not your line.
When to use this calculator
- Deciding whether to start a game download tonight or leave it running overnight.
- Planning a data migration window before maintenance.
- Comparing plans: is 500 Mbps worth it if the server caps at 100 Mbps?
- Estimating how long a backup restore will take at the office.
- Scheduling a 4K film download around a household's streaming hours.