Download Time Calculator
Enter a file size and a connection speed to see how long a download or upload takes.
What this tool does
Download time is the file size in bits divided by the speed in bits per second. A 1 GB file is 8 billion bits, so on a 100 Mbps connection it takes 80 seconds. Enter your own file size and speed above, and add a slowdown percentage for realistic results.
Converts file sizes and connection speeds into the same unit and divides one by the other.
Shows the result as a duration and in seconds, minutes and hours.
How to use it
- Enter the file size and choose its unit.
- Enter the connection speed and choose Mbps, MB/s or another unit.
- Optionally add a slowdown percentage for overhead and congestion.
- Read the time and copy or download it.
Why use this calculator
Takes the file size in bytes and the speed in bits or bytes per second, and does the unit conversion that people usually get wrong, including decimal against binary sizes. Internet plans are sold in megabits a second while files are measured in megabytes, a factor of eight apart, which makes the time to download a game, a backup or a video hard to guess.
Why we built it
We built the download time calculator to handle the megabit against megabyte confusion and to allow for real-world slowdown. Convert sizes with the file size converter and speeds with the data transfer rate converter.
Who this tool is for
- Gamers and streamers planning big downloads
- People backing up or uploading large files
- Anyone comparing internet plans
When to use it
- Estimating how long a large game or update will take.
- Planning an overnight backup or cloud upload.
- Checking whether a video will upload before a deadline.
- Choosing between connection plans.
How it works
Time (seconds) = file size in bytes × 8 ÷ speed in bits per second. A megabit per second is 1,000,000 bits a second and a byte is 8 bits, so 100 Mbps is 12.5 megabytes a second. File sizes can be counted in decimal (1 MB = 1,000,000 bytes) or binary (1 MB = 1,048,576 bytes); the tool lets you choose. The slowdown percentage reduces the speed before dividing.
Example: 1 GB (decimal) at 100 Mbps. 1 GB = 8,000,000,000 bits; 8,000,000,000 ÷ 100,000,000 = 80 seconds, or 1 minute 20 seconds. With a 50% slowdown the same download takes 2 minutes 40 seconds.
Real speeds depend on the server, your Wi-Fi, other devices and your provider, so treat the result as a best case unless you add a slowdown.
A worked example
These are the values the calculator opens with, so you can see exactly what it does with them. Change any value on the page and the result updates; the figures below come from the same calculation.
| Input | Value |
|---|---|
| File size | 1 |
| Size unit | GB |
| Size counted as | Decimal (1 MB = 1,000,000 bytes) |
| Connection speed | 100 |
| Speed unit | Mbps (megabits a second) |
| Real-world slowdown | 0 |
With those inputs, the calculator returns:
- Download time: 1 min 20 s
- Seconds: 80
- Minutes: 1.33
- Hours: 0.022
- Speed used: 12.5 MB/s (100 Mbps)
- File size in megabytes: 1,000 MB
What you give it, and what you get back
| Item | Details |
|---|---|
| File size and unit | A size in bytes, KB, MB, GB or TB, counted as decimal or binary. |
| Speed and unit | Kbps, Mbps, Gbps, KB/s or MB/s. |
| Slowdown | Optional percentage to allow for overhead and congestion. |
| Output | Time as a duration, in seconds, minutes and hours, and the speed in MB/s and Mbps. |
Issues you may run into
| What you see | Why it happens | What to do |
|---|---|---|
| The result is faster than I see | Plan speed is a maximum. | Add a slowdown of 10-30% or use a measured speed. |
| I mixed up Mb and MB | Lowercase b is bits and uppercase B is bytes. | Choose the unit shown on your plan or download manager. |
| Upload takes longer than I expect | Upload speeds are often much lower than download speeds. | Use your upload speed from a speed test. |
Assumptions and limitations
- Assumes a steady speed for the whole transfer.
- Does not model data caps or throttling.
Frequently asked questions
How long does it take to download 1 GB?
At 100 Mbps, about 80 seconds. At 10 Mbps it is about 13 minutes 20 seconds.
How do I convert Mbps to MB/s?
Divide by 8. 100 Mbps is 12.5 MB/s.
Why is my download slower than my plan speed?
Protocol overhead, Wi-Fi, server limits and other devices all reduce the real speed.
What is the difference between MB and MiB?
A megabyte is 1,000,000 bytes and a mebibyte is 1,048,576 bytes. The tool lets you pick either way of counting.
Can I use it for uploads?
Yes. Enter your upload speed instead of your download speed.
Is my information sent anywhere?
No. The calculation runs in your browser and nothing leaves the page.