Rental days are calculated on a 24-hour clock. In order to avoid being charged an additional day, you will need to enter the same pick-up and drop-off time. For example, if you request a rental car for pick up on Friday at 9:00am and drop off on Saturday at 9:00am, which is considered a one-day rental. However, if you request a rental car for pick-up on Friday at 9:00am and drop-off on Saturday at 12:00pm noon, it is considered a TWO-DAY rental because rental days are calculated in 24-hour time blocks.