How long will it take to download 800mb with 70mbps download speed?

And 81mbps upload speed. I'm download software for my iphone. And would you consider this a fast or slow connection? Sorry i don't understand this whole mbps stuff

OK, the first thing you need to know is there's a difference between MB and Mb. You need to be careful with the notation or it's easy to get confused. The capital B = Bytes. The lower case b = bits.

Quick lesson - Download speeds are usually quoted in Mega-bits (Mb). File sizes are quoted in Kilo-bytes (KB), Mega-Bytes (MB) and Giga-bytes (GB).

Couple of identifiers:

1 byte = 8 bits
1KB = 1, 024 Bytes (due to the rules of binary which is what a computer is based on).
1MB = 1, 024 KB

1Mb = 1 Million bits

Your file size is probably 800MB (Mega-Bytes)

Your download speed is 70Mbps (Mega-bits per second), which is 70, 000, 000 (70 Million) bits per second

So, to work out the estimated time:

800MB = 800 * 1024KB = 819, 200KB

=> 819, 200KB = 838, 860, 800 Bytes (multiply by 1, 024 as per above)

Converting to bits (multiply by 8) = 6, 710, 886, 400 bits

So, to download 6.7 billion bits at 70Mbps = 6, 710, 886, 400 / 70, 000, 000 = 95.87 seconds.

Roughly 1.5 minutes.

Now, broadband speeds fluctuate wildly so you won't get a constant speed, but it may go up as well as down.

This is a fairly good speed in relative terms. Most people's broadband will struggle to be even a quarter of that speed.

You'll typically find it will take 2 to 5 minutes for the iPhone software update and it will vary at different times of the day.