UsefulTab
Download Time Calculator
How long a file takes to transfer.
Calculate download and transfer time
Enter how big the file is and how fast your connection is, and this calculator shows how long the transfer takes and the exact time of day it would finish if it started now. The important detail it gets right is the bits-versus-bytes conversion: internet speeds are quoted in megabits per second (Mbps), but file sizes are in megabytes (MB), and there are 8 bits in a byte — so a 100 Mbps line moves about 12.5 MB each second, not 100. Pick MB/s directly if your tool already reports byte rate. Sizes and speeds use the base-10 figures ISPs and drive makers advertise (1 GB = 1,000 MB, 1 Gbps = 1,000 Mbps). The result updates as you type, and the finish time re-checks the clock each second. All the arithmetic happens in your browser.
Common questions
Why is a 100 Mbps connection not 100 MB per second?
Because speeds are measured in bits and file sizes in bytes, and a byte is 8 bits. 100 megabits per second divided by 8 is 12.5 megabytes per second, so a 1 GB file takes about 80 seconds on a perfect 100 Mbps link. This tool does that divide-by-8 for you when you pick a Mbps or Gbps speed, and skips it when you pick MB/s.
Does it use base-10 or base-2 units?
Base-10, to match how connections and drives are advertised: 1 MB = 1,000,000 bytes and 1 Mbps = 1,000,000 bits per second. That makes the numbers line up with your ISP's plan and a drive's labelled capacity rather than the binary (MiB) figures an OS sometimes shows.
Is the finish time a real prediction?
It is the ideal time assuming the full speed you entered with no interruptions — now plus the computed duration. Real transfers vary with network congestion, protocol overhead, and disk speed, so treat it as a best case. The clock re-bases on the current time every second so it stays current while the page is open.
Can I use it for uploads too?
Yes. The math is identical — just enter your upload speed instead of your download speed. Remember that most home connections upload slower than they download.
Is anything I enter uploaded?
No. It is pure arithmetic done in your browser. The size and speed you type are never sent to a server.