size ÷ speed = time
Download time calculator
A 1 GB file downloads in 80 seconds at 100 Mbit/s: the file is 8000 megabits and the line moves 100 of them every second. Enter a size and a speed to see the time for your own download.
- 1 GB ÷ 100 Mbit/s = 0:01:20
- 4.7 GB ÷ 25 Mbit/s = 0:25:04
The time updates as you type. It is the best case: the rated speed is a ceiling, so lower the share field to match the speed you usually get.
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At a glance
- Price
- No charge
- Account
- None needed
- Upload
- Not applicable — you type numbers, nothing is sent anywhere
- Formula
- File size in bits ÷ speed in bits per second
- Size units
- B, kB, MB, GB, TB, KiB, MiB, GiB and TiB
- Speed units
- kbit/s, Mbit/s, Gbit/s, kB/s, MB/s, GB/s and MiB/s
Download time at common sizes and speeds
These tables use the same formula as the calculator, at the full rated speed. Times read hours:minutes:seconds.
| File size | 10 Mbit/s | 50 Mbit/s | 100 Mbit/s | 500 Mbit/s | 1000 Mbit/s |
|---|---|---|---|---|---|
| 100 MB | 0:01:20 | 0:00:16 | 0:00:08 | 0:00:02 | 0:00:00.80 |
| 500 MB | 0:06:40 | 0:01:20 | 0:00:40 | 0:00:08 | 0:00:04 |
| 1 GB | 0:13:20 | 0:02:40 | 0:01:20 | 0:00:16 | 0:00:08 |
| 5 GB | 1:06:40 | 0:13:20 | 0:06:40 | 0:01:20 | 0:00:40 |
| 20 GB | 4:26:40 | 0:53:20 | 0:26:40 | 0:05:20 | 0:02:40 |
| Rated speed | Megabytes per second |
|---|---|
| 10 Mbit/s | 1.25 MB/s |
| 50 Mbit/s | 6.25 MB/s |
| 100 Mbit/s | 12.5 MB/s |
| 500 Mbit/s | 62.5 MB/s |
| 1000 Mbit/s | 125 MB/s |
How to work out a download time
Enter the file size
Type the size and pick its unit. Decimal units (kB, MB, GB) and binary units (KiB, MiB, GiB) are both offered, because they differ by about 4.9% at megabyte sizes and 7.4% at gigabyte sizes.
Enter the connection speed
Type the speed and pick its unit. Lines are usually sold in bits per second (Mbit/s), while browsers and download managers show bytes per second (MB/s). One byte is eight bits, so 100 Mbit/s is 12.5 MB/s.
Read the time
The time appears as hours:minutes:seconds and as plain seconds, next to the transfer rate. If your real speed is lower than the rated one, change the share field.
How download time is calculated
Download time is the file size in bits divided by the speed in bits per second. A byte is eight bits, so a 1 GB file is 8000 megabits. At 100 Mbit/s that takes 80 seconds; at 8 Mbit/s it takes 1000 seconds, which is 16 minutes 40 seconds.
The result is a best case. A rated speed is the most a line can carry, and real transfers usually fall short of it because of protocol overhead, a weak wireless signal, a busy server or other devices sharing the line. The share field scales the speed, so at 50% the time doubles. The calculator does not measure your connection and sends nothing anywhere.
Download time questions
How long does it take to download 1 GB?
At 100 Mbit/s a 1 GB file takes 80 seconds (0:01:20), at 10 Mbit/s it takes 800 seconds (0:13:20) and at 1 Gbit/s it takes 8 seconds. These are best-case figures at the full rated speed.
What is the difference between Mbit/s and MB/s?
Mbit/s is megabits per second and MB/s is megabytes per second. One byte is eight bits, so divide a speed in Mbit/s by 8 to get MB/s: 100 Mbit/s is 12.5 MB/s, and 1 Gbit/s is 125 MB/s.
Why is my real download slower than the result?
The calculator uses the rated speed of the line. Real transfers are slowed by protocol overhead, the wireless signal, the server's own limit and other traffic on your connection. Enter the speed you usually measure, or lower the share field, to get a realistic time.
Should I use MB or MiB for the file size?
Use the unit the number was given in. A size in MiB or GiB counts in powers of 1024, a size in MB or GB in powers of 1000. A 700 MB file is about 667.6 MiB, so choosing the wrong one changes the time by roughly 5% at megabyte sizes and 7% at gigabyte sizes.
Can I work out an upload time too?
Yes. Upload time uses the same formula with your upload speed in place of the download speed. Many connections upload more slowly than they download, so use the upload figure.
Does this calculator measure my connection or send my numbers anywhere?
No. It only does arithmetic on what you type, in your browser tab, and it never measures or contacts anything. With the page already loaded it also works offline.