The 160 year leap day

We all know about the leap year, every 4 years we add 1 day to compensate for Earths not so exact orbit around the Sun.

365.256363004 days per 1 Earth orbit

After 4 years it comes to 1461.025452016 days.

This means there is still 0.025452016 days unaccounted for.

After 160 years (40 x 4 leap years) that extra time will need to have yet another day to compensate.



So what is it called? If we don't have an extra day every 160 years the calendar would be off. In 4,800 years the calendar would be off by 1 full month.



So, since the birth of the US, our calendars are off by 1 day......not considering any other special changes.