Hi All > On 28 Jun 2011 at 0:32, Keith Meintjes wrote: >> I bought a spreadsheet, not a dumb table. I beg to differ! We all bought a dumb table instead of a spreadsheet especially if we have bought Excel. I have not been following this thread since I long ago gave up trying to use excel for date and time calculations. The programmers have taken a short-cut by using the PC BIOS date and time for calculations, assuming that we will only live during that period. On most machines the first BIOS day is 1st Jan 1900. The PC cannot go below that date as this is the "beginning of the world".! "Life" in the PC world is also only (usually?) 23 hours and 59 minutes long. It does not live for say perhaps 123 hours. I now live in the "real world" and for anything beyond that I use PAF to calculate differences in years in the "unreal" world. This way I do not get frustrated and so shorten my life to that of the PC! It takes longer but then hey I'll live longer too! ;o) Regards Mike