Download time calculator.
Estimate how long a download will take. Enter the file size and your connection speed in megabits per second and the calculator gives the time in hours, minutes and seconds.
File and connection
LiveSpeeds are in megabits and files in megabytes, and there are 8 bits in a byte, so the size is multiplied by 8 before dividing by the speed.
Download time
1 min 20 s
at this size and speed
An ideal estimate using decimal units (1 GB = 1000 MB). Real downloads are slower due to overhead and shared bandwidth. Calculations run in your browser; nothing you enter is stored.
How it works
Bits, bytes and speed
Internet speeds are quoted in megabits per second, but file sizes are in megabytes, and a byte is eight bits. To find a download time you convert the file to megabits by multiplying its size in megabytes by 8, then divide by the connection speed.
A 1 GB file is 1000 MB, or 8000 megabits, so at 100 Mbps it takes about 80 seconds, which is 1 minute 20 seconds. The calculator handles MB, GB and TB and formats the result into hours, minutes and seconds.
Reference
Download time for a 1 GB file.
How long a 1 GB file takes to download at common connection speeds.
| Speed (1 GB file) | Time |
|---|---|
| 10 Mbps | 13 min 20 s |
| 25 Mbps | 5 min 20 s |
| 50 Mbps | 2 min 40 s |
| 100 Mbps | 1 min 20 s |
| 500 Mbps | 16 s |
| 1000 Mbps | 8 s |
The full guide
The complete guide to download time.
Why bits and bytes matter, what slows downloads, and how to read the estimate.
Bits versus bytes
The single most common mistake is mixing bits and bytes. Connection speed is in megabits per second (Mbps), while files are measured in megabytes (MB), and there are eight bits in every byte. So a 100 Mbps line moves about 12.5 megabytes per second, not 100.
This calculator multiplies the file size by 8 to convert to megabits before dividing by your speed, which is why the time is longer than people expect.
What slows real downloads
The estimate assumes you get your full advertised speed with no losses, which rarely happens. Network overhead, Wi-Fi interference, a busy server, shared household bandwidth and throttling all cut into real throughput.
A good rule of thumb is to expect real downloads to be somewhat slower than the ideal figure, especially on wireless connections.
Decimal versus binary sizes
This tool uses decimal units, where 1 GB is 1000 MB, matching how internet providers and most download sites quote sizes and speeds. Some operating systems use binary units where 1 GB is 1024 MB, which makes a small difference.
For everyday download planning the decimal figure is the right one to use.
Using the estimate
Knowing the time helps you decide whether to download now or later, whether a connection is fast enough for large files, and how an upgrade would help. Doubling your speed roughly halves the time.
For uploads, the same maths applies using your upload speed, which is often lower than download.
The formula
Size times 8
over speed.
Download time is the file size in megabits, that is megabytes times 8, divided by the speed in megabits per second.
Distance calculator ›# Download time
megabits = size_MB × 8
seconds = megabits / speed_Mbps
# 1 GB at 100 Mbps
8000 / 100 = 80 s (1 min 20 s)Questions
Download time questions.
How do I calculate download time?
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Multiply the file size in megabytes by 8 to get megabits, then divide by your speed in Mbps. Enter the size and speed above and the calculator gives the time.
Why is the download slower than my speed suggests?
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Because speed is in megabits but files are in megabytes, and a byte is 8 bits. A 100 Mbps line moves about 12.5 MB per second, so a 1 GB file takes around 80 seconds.
How long to download a 1 GB file?
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At 100 Mbps, about 80 seconds in ideal conditions. At 50 Mbps it is roughly 2 minutes 40 seconds. Real speeds are usually a bit slower.
Does this use real-world speeds?
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No, it is an ideal estimate. Overhead, Wi-Fi, busy servers and shared bandwidth make real downloads slower than the calculated time.
Is this download time calculator free?
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Yes. It is completely free with no sign-up, and every calculation runs locally in your browser, so nothing you enter is stored or sent anywhere.
About the developer
Jean Borg
Jean builds and maintains every calculator on freecalculators.pro from Malta, with a focus on tools that are fast, free and show their working. The download time calculator converts file size and speed into a time, handling the bits and bytes for you.