Are there any sites or easy methods of finding out it would take for file transfer over different speed links?
For example, I need to find out how long it would take to download/transfer file of 75G with a transfer rate of 2 Mbps.
Are there any sites or easy methods of finding out it would take for file transfer over different speed links? For example, I need to find out how long it would take to download/transfer file of 75G with a transfer rate of 2 Mbps. 


Answer : 3 Days 15 Hours 22 Minutes 52.8 Seconds. Hope this site will help you. 


It depends on what you actually mean by Mbps, but I would reccomend Wolfram Alpha for things like this  it can do a lot more than you think. Anyway, here's a screenie of your query: 


75GB can be either 75000000000 bytes (in SI units), or 80530636800 bytes (in IEC units) A byte is 8 bits, so we are talking either
or 644245094400 bits A Mbps is either
or
So divide the number of bits by the number of bits per second to get the number of seconds:



300,000 seconds, assuming you meant



Here is a method I came up with that is easy to remember for rough estimation. Short answerMultiply the file size in gigabytes by 9000 and then divide it by the speed of your connection in megabits per second. The resulting number is in seconds, which you can then convert into days, hours, and minutes using your favorite conversion program. Example75 GB × 9000 / 2 Mb/s = 337500 s ≈ 3 days 22 hours ExplanationConsider overhead imposed by the Ethernet, IP, and TCP protocols. The IPv4 header is 20 octets long, not counting any option headers. The TCP header is also 20 octets long, not counting any option headers. An Ethernet connection can carry 1500 octets of data per 1538 octet frame (1542 if VLAN tagging is used) using Ethernet II framing (for PPPoE encapsulated connections, only 1492 octets). Then, do the math: [ 1500 o (Ethernet data)  20 o (IPv4)  20 o (TCP) ] / 1538 o (Ethernet frame) ≈ 95% efficiency [1024 Mio/Gio] * [8 Mb/Mio] / 94.92848% ≈ 8630 9000 is the nearest multiple of 1000; it is both easier to remember and less optimistic. 


It's 3 days, 22 hours. Things not to forget: 1) Data sizes are measured in binary units, line speeds in decimal units. 2) There are 8 bits in a byte. 3) The line has to carry address and control information, not just data. 4) You can't pack the line 100% with information. 


There is small program for this (Tembo Transfer Time Estimator). After usage it I got: 75 GB on 2 Mbps and network efficiency 90% will be transfered in 3 days, 22 hours, 48 minutes, 53.33 seconds with average speed 230.4 KB/s. Check it yourself at http://tembolab.pl/products/transfertimeestimator.html. 

