Excel dates counted differently and a reliable way of working out the day of the week

Following my recent post about 40,000 days, I got a couple of emails telling me that Excel disagrees about when the 40,000th day is. And this is true – Excel counts Day 40000 as July 6th 2009, not July 7th. Unfortunately for Excel users, they’re wrong. And it’s down to the fact that Excel thinks that 1900 was a leap-year, when we all know it wasn’t. You see, leap-years only fall on the century year if the year is divisible by 400. So 2000 was a leap-year, but 1900 wasn’t, and 2100 won’t be either. What’s more, this has been … Continue reading Excel dates counted differently and a reliable way of working out the day of the week