# How To Add Time In Excel Or Numbers

This one had me going for a while the other day. I had a cell with a time in it, and just wanted to add 15 minutes to it and place it in the cell next to it. Anyway, the way to do this is to add (or subtract) #Minutes/1440.

For example, if cell A1 has the time 6:15 in it, and you want to add 15 minutes to it for cell A2 simply set it =A1+(15/1440).

The reason for this is that Excel (and Numbers, and.. most likely any other spreadsheet software out there) keeps track of dates, not time – so if you have a date of 6/19/2009, and in the next cell you want 6/20/2009 – you add 1. Well, there are 1440 minutes in a day, so you simply have to add a fraction of a day equal to the amount of time you want to add. So 15/1440 = 0.0104166667 days.

# Calculating Actual Hard Disk Space…

If under 1TB in size simply calculate: (Advertised size in GB) * 0.931
Or, to be exact: (Advertised size in GB * 10^9)/1024^3 should do the trick…

Over one TB you can not just assume 1TB = 1,024GB since the advertising calculation is in base 10, and this crazy device in front of you prefers base 2… So:
Over 1TB calculate: (Advertised size in TB) * 0.909
Once again, to be precise: (Advertised size in TB * 10^12)/1024^4.