Days between 2 dates in Excel
To determine that days between 2 dates in Excel you have a few options and a new function in Excel 2013.
Excel versions prior to Excel 2013
As explained in other blog posts, dates in Excel are actually just numbers. Excel is being nice to you by showing it in a human friendly format but it sees a date as the number of days from the 1 January 1900.
If your date is a valid date in Excel (more about this here- very important) then you can simply do normal arithmetic and subtract one date from the other. Depending on how you do it, it may come up with a strange answer (another date, probably in the early 1900’s). This is because it is formatting the number of days (which should just be a number) to date format. Change the format back to General or a number format and you should see the number you expect.
You may need to add or subtract one day from the answer depending on what you are trying to achieve.
Excel 2013 new DAYS function
In Excel 2013, you can do all the things mentioned above, but there is also a new DAYS function. All it asks is that you point to a Start Date and an End Date and it will give you the answer. Easy enough but for compatibility reasons we recommend you use the other method until Excel 2013 is used by everyone.