How do I keep Excel from changing my date format?

Pretty basic question for a more advanced user than me but I can't seem to find an option.

I am working on an order form for my clients to fill out by plugging data into a preformatted spreadsheet. However, I am using a date format that apparently Excel doesn't like.

This: 01-31-15

Keeps changing to this: 1/31/2015

This just really doesn't work with what I am doing and I don't want to retype every date on every order.

I've tried making it a General text field, there are no existing functions in the cell but then it changes my setting to a date field and just keeps reformatting. I've also tried cursing at it and that didn't help either. :)

Solution 1:

Try specifying a custom number format of mm-dd-yy, that should do the trick.

Incidentally, General is a number format that can cause headaches sometimes - Excel decides for itself what type of value it thinks you entered in a cell. I tend to stay away from General and explicitly pick my number formats where possible.