When dates in a worksheet aren't in the order you want, you can sort them. For example, you can sort them from oldest on top to newest on top. Unsorted dates. You can quickly create a list of dates in sequential order by using the Fill Applies To: Excel Excel Excel Excel Excel for Mac Excel. You need to create custom sort To do custom sort please follow below steps: Can I use a formula or some other Excel trick to get all of the back-to-back months to fall into chronological order. Essentially, I need a function.