What this calculator does
Download time depends on two things: how big the file is and how fast the connection actually delivers data. Internet plans are advertised in megabits per second (Mbps), but file sizes are almost always shown in megabytes or gigabytes, and a byte is 8 bits, so the two units have to be reconciled before a sensible time comes out the other end.
This calculator does that conversion for you: enter the file size in MB or GB and the download speed in Mbps, and it works out the time assuming the connection runs at that speed for the whole transfer. Real downloads are often slower than the advertised plan speed due to server limits, network congestion or Wi-Fi overhead, so treat the result as a best case rather than a guarantee.
The formula
File size is first converted to megabits by multiplying megabytes by 8 (or gigabytes by 8,000). Dividing that figure by the download speed in Mbps gives the time in seconds, which is then converted to a more readable minutes-and-seconds or hours-minutes-seconds format.
| Term | Meaning |
|---|---|
| Mbps | Megabits per second, the unit connection speeds are almost always advertised in. |
| MB / GB | Megabytes and gigabytes, the units file sizes are shown in. One byte equals 8 bits. |
| Throughput | The effective transfer rate once the megabits-to-megabytes conversion has been applied, shown here in MB/s. |
The inputs explained
| Field | What to enter |
|---|---|
| File size | The size of the file being downloaded. |
| Size unit | Whether the size above is in megabytes or gigabytes. |
| Download speed (Mbps) | Your download speed in megabits per second, as advertised by your plan or measured by a speed test. |
When to use it
Planning around a large game or software update
Before starting a multi-gigabyte download, working out the expected time helps decide whether to start it now or leave it running overnight.
Choosing between internet plans
Comparing the time a typical file takes on two different advertised speeds makes the practical difference between plans concrete, rather than just comparing Mbps numbers in the abstract.
Diagnosing a slow connection
If a download is taking far longer than this calculator predicts for the advertised speed, that points to a problem with the connection, the server, or something else on the network competing for bandwidth.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How long does a 5 GB file take at different connection speeds?
The same 5 GB file downloaded at a range of common connection speeds.
| Download speed | Download time | Effective throughput |
|---|---|---|
| 10 Mbps | 1:06:40 | 1.25 MB/s |
| 25 Mbps | 26:40 | 3.13 MB/s |
| 50 Mbps | 13:20 | 6.25 MB/s |
| 100 Mbps | 6:40 | 12.50 MB/s |
| 250 Mbps | 2:40 | 31.25 MB/s |
| 1000 Mbps | 0:40 | 125.00 MB/s |
Questions
Why is my download slower than my plan speed suggests?
Advertised speeds are a maximum, not a guarantee. The server sending the file, Wi-Fi overhead, other devices sharing the connection and network congestion can all reduce the actual throughput below the plan figure.
Why is download time different from upload time on the same connection?
Most home internet plans are asymmetric, meaning the advertised download speed is higher than the upload speed. Use the upload time calculator for the reverse case of sending a file.
Why does the file size need a unit conversion at all?
Connection speeds are measured in megabits per second while file sizes are shown in megabytes or gigabytes, and a byte is 8 bits. Without converting one to match the other, the numbers cannot be divided meaningfully.
Does this account for the time a browser or app takes to start the download?
No, it only estimates the raw data transfer time based on file size and connection speed. Any delay before the transfer begins, such as server response time, is not included.
For estimating how long the reverse transfer, sending a file, will take, see the upload time calculator.