Download Time Calculator
Estimate how long any download will take from the file size and your connection speed — with the megabit-to-megabyte maths done correctly.
How download time is calculated
Download time is simple in principle: file size ÷ connection speed. The catch that trips everyone up is units. Internet speeds are sold in megabits per second (Mb/s), but files are measured in megabytes (MB), and there are eight bits in a byte. So a 100 Mb/s connection moves only about 12.5 MB each second, not 100. This calculator converts everything correctly and shows both the theoretical best time and a realistic estimate.
Why two numbers? In the real world you rarely get the full advertised speed. Protocol overhead, Wi-Fi signal, a busy server, and other devices sharing your line typically shave 10–20% off. We apply a sensible ~85% efficiency factor for the realistic figure, which is closer to what you will actually see.
Typical download times
| File | Size | 10 Mb/s | 100 Mb/s | 1 Gb/s |
|---|---|---|---|---|
| Music album | 100 MB | ~94 s | ~9 s | ~1 s |
| HD movie | 5 GB | ~1 h 18 m | ~7.8 min | ~47 s |
| PC game | 80 GB | ~20.9 h | ~2.1 h | ~12.5 min |
| Phone photo backup | 30 GB | ~7.8 h | ~47 min | ~4.7 min |
Realistic estimates at ~85% efficiency, decimal file sizes.
Slow downloads on a fast plan? The bottleneck is often Wi-Fi rather than your internet speed. Try a wired connection or move closer to the router, and see our home Wi-Fi guide. To free up space for big downloads, read how to free up storage.
Frequently asked questions
Why is my download slower than my internet speed?
Two reasons. First, plans are sold in megabits but files are in megabytes, and there are eight bits per byte — so 100 Mb/s is only about 12.5 MB/s. Second, real-world overhead, Wi-Fi and busy servers typically cost another 10–20%. This calculator accounts for both.
Is the calculator using bits or bytes?
Both, correctly. You choose your speed unit (Mbps for megabits, or MB/s for megabytes) and your file-size unit, and the tool converts between them. Speeds quoted by ISPs are almost always megabits (Mbps).
What does the 85% efficiency figure mean?
It is a realistic adjustment. You rarely achieve 100% of your line speed because of protocol overhead, signal quality and server limits. We show the theoretical best and a more honest ~85% estimate so you are not surprised.
Does Wi-Fi affect download time?
Yes, often more than your internet plan. A weak Wi-Fi signal can cap speeds well below what you pay for. For large downloads, a wired Ethernet connection or sitting near the router gives the most consistent result.
How long to download a 50 GB game on 100 Mbps?
About 78 minutes at a realistic ~85% efficiency. On a gigabit connection it drops to roughly 8 minutes. Enter the exact size and speed above for your own figure.
This tool runs entirely in your browser — nothing you type is sent to our servers. Tudug is reader-supported and may earn from ads.
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