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Years with Same Calendar as 1666

The year 1666 had 365 days and started on a Friday (Wallis and Futuna, Gregorian calendar).

This country introduced the modern Gregorian calendar in year 1582, so previous years are based on the Julian calendar. In that calendar system, a Leap Day was added every four years, without the exceptions defined in today's Gregorian calendar. This affects the selection of years listed here.

Years with same starting weekday and equal number of days to 1666
YearCompared to year 1666Since last
157492 years before 
Wallis and Futuna adopted today's Gregorian calendar in 1582. All previous years are based on the Julian calendar.
159373 years before+ 19 years
159967 years before+ 6 years
161056 years before+ 11 years
162145 years before+ 11 years
162739 years before+ 6 years
163828 years before+ 11 years
164917 years before+ 11 years
165511 years before+ 6 years
1666selected year+ 11 years
167711 years after+ 11 years
168317 years after+ 6 years
169428 years after+ 11 years
170034 years after+ 6 years
170640 years after+ 6 years
171751 years after+ 11 years
172357 years after+ 6 years
173468 years after+ 11 years
174579 years after+ 11 years
175185 years after+ 6 years
176296 years after+ 11 years
20 years share the calendar of year 1666 in the 200-year time span from 1566 to 1765.
Note that holidays will not match exactly. Selected year is highlighted.

Extend to 1100 – 2099

Which Years Have the Same Calendar?

Reuse your yearly calendar by finding years that have the same number of days and start on the same day of the week.

Which Months Have the Same Calendar?

Find months that have the same number of days and start on the same day of the week.

When Does a Date Fall on a Certain Weekday?

Do you feel dates like Friday the 13th occur often? This calculator tells you exactly when.