Transfer Time Estimator
How long will it take to transfer your file? Enter size and speed to find out.
Time
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File (Bits)
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Speed (Bps)
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About this tool
Transfer Time Estimator
Transfer Time Estimator tells you how long a file will take to move at a given connection speed, and shows the same file at a range of common speeds so you can see what upgrading would actually buy you.
How to use it
- Enter the file size and pick its unit: KB, MB, GB or TB.
- Enter the transfer speed and pick its unit. Both bit rates (Kbps, Mbps, Gbps) and byte rates (KB/s, MB/s, GB/s) are supported.
- Read the estimated time, and the comparison table of the same file at common speeds.
Bits, bytes, and the factor of eight
The single biggest source of confusion is that connection speeds are quoted in bits per second while file sizes are given in bytes. There are eight bits in a byte, so a 100 Mbps connection moves at most about 12.5 MB per second.
Real transfers never hit the theoretical figure. Protocol overhead, latency, disk speed and contention with other traffic typically cost 10 to 20 percent, so treat the result as a floor rather than a promise.
Worked example
The default case, a 1 GB file on a 100 Mbps connection:
- File size1 GB = 8,000 megabits
- Speed100 Mbps
- Calculation8,000 / 100
Result: About 80 seconds at the theoretical maximum. Expect closer to 90 to 100 seconds in practice.
When it helps
- Deciding whether to wait for an upload or start it and walk away.
- Checking whether a faster internet plan would meaningfully change your workflow.
- Estimating a backup or sync window before you start one.
- Explaining to someone why their 100 Mbps connection does not download a 1 GB file in ten seconds.
Common mistakes
- Reading Mbps as megabytes per second. It is megabits, and the difference is a factor of eight.
- Forgetting that upload speed is usually much slower than download on home connections.
- Assuming the bottleneck is the network. On fast connections the hard drive or the far-end server is often the limit.
