The Gregorian calendar repeats every eleven years not fourteen !
Common years usually repeat after 6 or 11 years and leap years usually repeat after 28 years, except between most centuries. However, the calendar completely repeats every 400 years.
1848
It is either every 6th, 11th or 28th year, depending on how adding an extra day in a leap year affects it. Without leap years, a calendar would always repeat every 7th year. If in a 7 year period there is one leap year then one day will be skipped, so the next repeat comes around in 6 years. So if you take from 2013 to 2019 inclusive, 2016 is the only leap year of those 7 years. 2013 and 2019 have identical calendars. The pattern is that a leap year repeats its calendar every 28 years. The year after a leap year repeats in 6 years. Two years after a leap year, which is also two years before a leap year, repeats every 11 years and 3 years after a leap year, which is also one year before a leap year, repeats every 11 years. 2012, a leap year, will repeat in 2040. 2013, a year after a leap year, repeats in 6 years, in 2019. 2014, two years after/before a leap year repeats 11 years later in 2025 and 2015, a year before a leap year will repeat 11 years later in 2026. 2013 and 2019 are repeats, but 2014 and 2020 aren't, because unlike 2014, 2020 is a leap year. If a leap year causes a day to be skipped, then it will come around again in the next cycle, so then you get an 11 year gap. A leap year itself is repeated every 28 years.
Calendar, in the present context, refers to the Gregorian calendar, because it is the one used most frequently, worldwide. In a Gregorian calendar, centuries are not leap years unless divisible by 400 (Eg: The year 2000 is a leap year, whereas 1900 isn’t).As in the picture below, there can be only 14 calendar patterns - 1 to 14 (Years starting from Sunday to Saturday, either leap or non-leap year). Any calendar repeats in a minimum gap of 6 years and a maximum gap of 40 years. All the patterns 1 to 14 occur at least once in a minimum span of 25 years (Eg: 2000 - 2024) and a maximum span of 40 (Eg: 1889 - 1928).1. Repetition in the succeeding years:I. Calendars of non-leap years:A. Calendars of non-leap years of the form 4n and 4n+1 repeat after 6 years. Eg: Calendar of the year 1900 repeats in 1906; that of 2017 repeats in 2023.B. Calendars of non-leap years of the form 4n+2 and 4n+3 repeat after 11 years. 
Eg: Calendar of the year 2018 repeats in 2029; that of 2019 in 2030.Exception: The years of the 90s of a century ending in a non-leap year do not follow this pattern. Calendar of such a year Y repeats after(a) 12 years, if Y ∈ {90, 91, 97, 98}Eg: Calendar of the year 1890 repeats in 1902.(b) 6 years, if Y ∈ {93, 94, 95, 99}Eg: Calendar of the year 1895 repeats in 1901.II. Calendars of leap years:Calendar of a leap year repeats afterA. 40 years, in the 70s and 80s of a century ending in a non-leap year.Eg: Calendar of the year 1872 repeats in 1912.B. 12 years, in the 90s of a century ending in a non-leap year.Eg: Calendar of the year 1892 repeats in 1904.C. 28 years, otherwise.Eg: Calendar of the year 2020 repeats in 2048.Note: Combining I and II, this is the order of repetition of calendars of the 90s of a century ending in a non-leap year:12 12 12 6 6 6 12 12 12 62. Occurrence in the preceding years:I. Calendars of non-leap years:A. Calendars of non-leap years of the form 4n and 4n+3 are the same as that of the 6th preceding year. 
Eg: Calendar of the year 1900 is the same as that of 1894; that of 2019 is the same as that of 2013.B. Calendars of non-leap years of the form 4n+1 and 4n+2 are the same as that of the 11th preceding year.
Eg: Calendar of the year 2021 is the same as that of 2010; that of 2022 is the same as that of 2011.Exception: The first ten years of a century ending in a leap year do not follow this pattern. Calendar of such a year Y is the same as that of(a) the 6th preceding year, if Y ∈ {01, 05, 06, 07}Eg: Calendar of the year 1905 is the same as that of 1899.(b) the 12th preceding year, if Y ∈ {02, 03, 09, 10}Eg: Calendar of the year 1910 is the same as that of 1898.II. Calendars of leap years:Calendar of a leap year is the same as that ofA. the 40th preceding year, in the second and third decade of a century ending in a leap year. 
Eg: Calendar of the year 1916 is the same as that of 1876.B. the 12th preceding year, in the first decade of a century ending in a leap year.
 Eg: Calendar of the year 1908 is the same as that of 1896.C. the 28th preceding year, otherwise.
 Eg: Calendar of the year 2024 is the same as that of 1996.Note: Combining I and II, this is the order of the immediate preceding years in which calendars of the first decade (01-10) of a century ending in a leap year, are the same:6 12 12 12 6 6 6 12 12 12
The 1969 calendar will repeat in the year 2045. The calendar repeats every 28 years.
No. 2004 was a leap year, but 2015 is not. It is not always the case that a calendar repeats every 11 years.
Every eleven years. The Gregorian calendar repeats in 11 year cycles.
The Gregorian calendar repeats every eleven years not fourteen !
Common years usually repeat after 6 or 11 years and leap years usually repeat after 28 years, except between most centuries. However, the calendar completely repeats every 400 years.
The Gregorian calendar repeats every 400 years. In 56 years of every 400-year period, the 25th of October falls on a Monday. That's an average of 14 years per century.
The calendar repeats every 11 years. Therefore - the next time April 20th will fall on a Saturday is 2024.
1848
The calendar for the year 1964 will repeat in the year 2024. This is because the calendar repeats every 28 years.
It is either every 6th, 11th or 28th year, depending on how adding an extra day in a leap year affects it. Without leap years, a calendar would always repeat every 7th year. If in a 7 year period there is one leap year then one day will be skipped, so the next repeat comes around in 6 years. So if you take from 2013 to 2019 inclusive, 2016 is the only leap year of those 7 years. 2013 and 2019 have identical calendars. The pattern is that a leap year repeats its calendar every 28 years. The year after a leap year repeats in 6 years. Two years after a leap year, which is also two years before a leap year, repeats every 11 years and 3 years after a leap year, which is also one year before a leap year, repeats every 11 years. 2012, a leap year, will repeat in 2040. 2013, a year after a leap year, repeats in 6 years, in 2019. 2014, two years after/before a leap year repeats 11 years later in 2025 and 2015, a year before a leap year will repeat 11 years later in 2026. 2013 and 2019 are repeats, but 2014 and 2020 aren't, because unlike 2014, 2020 is a leap year. If a leap year causes a day to be skipped, then it will come around again in the next cycle, so then you get an 11 year gap. A leap year itself is repeated every 28 years.
Yes; an entire cycle repeats every 29 1/2 days, approximately.Yes; an entire cycle repeats every 29 1/2 days, approximately.Yes; an entire cycle repeats every 29 1/2 days, approximately.Yes; an entire cycle repeats every 29 1/2 days, approximately.
A leap year is not a physical phenomenon. It is a property of many calendars that is added in an effort to keep it in sync with an actual cycle in nature, like, for example, the earth's orbit of the sun. In the Julian calendar, which is the predecessor to the Gregorian calendar, the most popular today in the western world, every fourth year is a leap year. In the Gregorian calendar, every fourth year is a leap year with the exception of three years out of every 400. The last exception was the year 1900, and the next exception is the year 2100. Regarding the relationship between the dates of the year and the days of the week, the Julian calendar completely repeats itself every 28 years, and the Gregorian calendar completely repeats itself every 400 years.