File size + speed → time
Download Time Calculator
Enter a file size and your connection speed to find out exactly how long the download will take.
Time = MB ÷ (Mbps ÷ 8)- 100% free
- No signup
- Instant results
- Exact 8-bit standard
How long will it take?
Change any field — the estimate updates instantly.
Estimated download time
Theoretical bestRealistic estimate
15 min 41 s
Allows for ~15% real-world overhead
Effective transfer rate
62.5 MB/s
- Accurate to the standard bits-to-bytes conversion (1 byte = 8 bits)
- No login required — 100% free
- Your data never leaves your browser
What this calculator tells you
A download time calculator estimates how long a transfer takes by dividing the file size by your connection speed. Convert your speed from Mbps to MB/s first by dividing by 8, then divide the file size in megabytes by that figure. A 1 GB file on a 100 Mbps connection takes about 80 seconds.
The formula
Time (s) = File size (MB) ÷ (Speed in Mbps ÷ 8)How download time is calculated
Two steps — the first one is where most people go wrong.
Convert the speed to MB/s
Your plan is quoted in megabits (Mbps) but files are measured in megabytes (MB). Divide the Mbps figure by 8. A 100 Mbps connection is 12.5 MB/s.
Divide the file size by that speed
Take the file size in megabytes and divide it by your MB/s figure. The answer is the transfer time in seconds — 1000 MB ÷ 12.5 MB/s = 80 seconds.
Subtract real-world overhead
Add roughly 10-20% to the result to account for protocol overhead, server limits and Wi-Fi. We show both the theoretical and the realistic figure.
Download time reference table
Common file sizes at common connection speeds, including the exact scenarios people search for.
| File size | Connection | Rate | Theoretical time | Realistic time |
|---|---|---|---|---|
| 100 MB | 400 Mbps | 50 MB/s | 2 s | 2.4 s |
| 135 MB | 12 Mbps | 1.5 MB/s | 1 min 30 s | 1 min 45 s |
| 3 MB | 3 Mbps | 0.38 MB/s | 8 s | 9.4 s |
| 700 MB | 50 Mbps | 6.25 MB/s | 1 min 52 s | 2 min 11 s |
| 1 GB | 100 Mbps | 12.5 MB/s | 1 min 20 s | 1 min 34 s |
| 5 GB | 200 Mbps | 25 MB/s | 3 min 20 s | 3 min 55 s |
| 25 GB | 500 Mbps | 62.5 MB/s | 6 min 40 s | 7 min 50 s |
| 50 GB | 500 Mbps | 62.5 MB/s | 13 min 20 s | 15 min 41 s |
| 50 GB | 1,000 Mbps | 125 MB/s | 6 min 40 s | 7 min 50 s |
| 100 GB | 940 Mbps | 117.5 MB/s | 14 min 11 s | 16 min 41 s |
Realistic times assume 85% line efficiency, which is typical for a wired connection to a healthy server.
Accuracy and assumptions
This tool reports a theoretical estimate based on your full advertised speed being available for the whole transfer. Real downloads from Steam, the Epic Games Launcher or a browser are commonly 10-20% slower because of protocol overhead, server-side rate limits, Wi-Fi conditions and bandwidth shared with other devices in the house. Treat the theoretical figure as a best case and the realistic figure as what you should actually plan around.
Things that change your real download time
Wi-Fi versus wired
A wired Ethernet connection almost always reaches closer to your plan's ceiling. Wi-Fi loses throughput to distance, walls, interference and older standards — often 30-50% on 2.4 GHz.
Downloads that start fast then slow down
Many services burst at full speed for the first few seconds, then settle at a lower sustained rate once server-side throttling kicks in. The average is what determines your total time.
Several downloads at once
Your connection is a fixed pipe. Two simultaneous downloads each get roughly half the bandwidth, so both take about twice as long as they would alone.
The server has limits too
You can only download as fast as the other end can send. A slow or overloaded host caps your speed no matter how fast your plan is.
Game installs are not only downloading
Steam and Epic decompress and write data to disk while downloading. On a slow hard drive, the disk — not your internet — becomes the bottleneck.
Just need the unit conversion?
If you only want to know what your plan's Mbps figure means in MB/s — without a specific file in mind — the main Mbps to MB/s calculator does exactly that, in both directions.
Who this is for
The gamer planning an overnight update
A 50 GB game on a 500 Mbps line takes about 14 minutes. On a 25 Mbps line it is closer to 4.8 hours — worth knowing before you start it at 11pm.
The remote worker on a deadline
Check whether a 6 GB project archive will upload before your call starts, or whether you need to send a link instead.
The traveller on hotel Wi-Fi
Enter the speed your test just reported and see whether that film will finish downloading before your flight boards.
Download time questions
The exact scenarios people search for, answered with the numbers.
About 2 seconds. 400 Mbps converts to 50 MB/s, and 100 MB ÷ 50 MB/s = 2 seconds. Allowing for real-world overhead, expect roughly 2.4 seconds.
About 90 seconds. 12 Mbps converts to 1.5 MB/s, and 135 MB ÷ 1.5 MB/s = 90 seconds, or one and a half minutes. In practice budget closer to 105 seconds.
About 8 seconds. A 3 Mbps connection delivers 0.375 MB/s, and 3 MB ÷ 0.375 MB/s = 8 seconds. Overhead on such a slow line typically pushes it to around 9-10 seconds.
About 80 seconds. 100 Mbps is 12.5 MB/s and 1 GB is 1000 MB, so 1000 ÷ 12.5 = 80 seconds. Expect around 94 seconds once overhead is included.
About 13 minutes 20 seconds in theory. 500 Mbps is 62.5 MB/s and 50 GB is 50,000 MB, giving 800 seconds. Because Steam reports binary sizes, a '50 GB' game is really 53.7 GB, so plan for 16-18 minutes.
Download time in seconds = file size in megabytes ÷ (connection speed in Mbps ÷ 8). Convert the speed to MB/s first, then divide the file size by it. Add 10-20% for real-world conditions.
Game launchers report binary gigabytes (1024 MB) but label them GB, so a listed 50 GB is 53.7 decimal GB of actual data. Steam and Epic also download separate patch data and temporary files during installation.
Every transfer loses some capacity to TCP/IP and TLS overhead, server-side rate limits, Wi-Fi interference and bandwidth shared with other devices. Losing 10-20% of the advertised speed is normal, which is why we show a realistic estimate alongside the theoretical one.
Private by design
This calculator is pure client-side JavaScript. The numbers you type are processed by your own browser and are never transmitted to us, logged, or stored anywhere. There is no account, no tracking of your inputs, and the whole site is served over HTTPS.
- No server round-trip — the maths happens on your device
- No login, no email, no personal data collected
- HTTPS everywhere, no mixed content
Last updated: Methodology & accuracy
Plan your next big download
Check the time before you start the transfer, not while you are waiting for it. Enter your file size and speed above and you will know within a second.