#VALUE error

[Baggeepants]

I am trying to get Excel to calculate the age of a person on a certain date but have found the formula I am using in column C =(YEAR(B1)-YEAR(A1)) works in some cells but most are returning the #VALUE error code. I have formatted the cells in column A & B as 'Date' & column C as 'Number' with zero decimal points. In rows 1, 3, 4 & 7 I expect the error code until I can correct the spreadsheet with the actual date but rows 2, 5 & 6 should show the approx. age of the person as rows 8 to 13 do. Is there another formula that can do this subtraction or does the formula I am using require tweaking?

 

[Gerald Higgins]

I think you've got two problems here.

First of all, Excel isn't very good at dealing with dates before the year 1900 / 1904 - try Googling it.
There are ways round that - for example you could try storing the year as a separate field from the rest of the date.

Second - if you have vague dates like "Jul-Sep 1884", Excel is always going to struggle to deal with that.
I'm guessing an entry like this means that the date is not known exactly, but it's some time between those months.
For these, I think you'll have to pick a specific data in the range, such as 1st July, or 30th September, or somewhere in between.