If something says less than 30 days does that mean it is too late ON day 30, since that isn't less than, but equal to?

Question

If something says less than 30 days does that mean it is too late ON day 30, since that isn't less than, but equal to?

Answer

Yes, but be sure the parties are in accord on the method of counting days and any other rules that might apply. Some systems treat the day the deal is made as day 1, but more typically the following day is day 1. Sometimes if the last day to perform an act is a Sunday, it can still be done on Monday. Rarely, only "business days" or "court days" are counted.