How much in late fee's can a landlord charge for rental property?

Question Details:

I was renting property and in my lease agreement my late fee was $15 a day for everyday after my allotted grace period. I didn't pay December's rent until February. Can The landlord charge me late fees up until I payed the rent or does it stop at December 31'st? I moved out January 22nd and payed the prorated rent agreed on for the month of January. Important Notice