Week numbers 421

421 has 52 ISO weeks. Week 1: Jan 4 – 10 · Week 52: Dec 27, 421 – Jan 2, 422

421 at a glance

Weeks in 42152
Week 1January 4, 421 – January 10, 421
Week 52December 27, 421 – January 2, 422
Days in 421365
Leap yearNo

All Weeks in 421

Week From To Month
Week 1 in 421 January 4, 421 January 10, 421 January
Week 2 in 421 January 11, 421 January 17, 421 January
Week 3 in 421 January 18, 421 January 24, 421 January
Week 4 in 421 January 25, 421 January 31, 421 January
Week 5 in 421 February 1, 421 February 7, 421 February
Week 6 in 421 February 8, 421 February 14, 421 February
Week 7 in 421 February 15, 421 February 21, 421 February
Week 8 in 421 February 22, 421 February 28, 421 February
Week 9 in 421 March 1, 421 March 7, 421 March
Week 10 in 421 March 8, 421 March 14, 421 March
Week 11 in 421 March 15, 421 March 21, 421 March
Week 12 in 421 March 22, 421 March 28, 421 March
Week 13 in 421 March 29, 421 April 4, 421 March / April
Week 14 in 421 April 5, 421 April 11, 421 April
Week 15 in 421 April 12, 421 April 18, 421 April
Week 16 in 421 April 19, 421 April 25, 421 April
Week 17 in 421 April 26, 421 May 2, 421 April / May
Week 18 in 421 May 3, 421 May 9, 421 May
Week 19 in 421 May 10, 421 May 16, 421 May
Week 20 in 421 May 17, 421 May 23, 421 May
Week 21 in 421 May 24, 421 May 30, 421 May
Week 22 in 421 May 31, 421 June 6, 421 May / June
Week 23 in 421 June 7, 421 June 13, 421 June
Week 24 in 421 June 14, 421 June 20, 421 June
Week 25 in 421 June 21, 421 June 27, 421 June
Week 26 in 421 June 28, 421 July 4, 421 June / July
Week 27 in 421 July 5, 421 July 11, 421 July
Week 28 in 421 July 12, 421 July 18, 421 July
Week 29 in 421 July 19, 421 July 25, 421 July
Week 30 in 421 July 26, 421 August 1, 421 July / August
Week 31 in 421 August 2, 421 August 8, 421 August
Week 32 in 421 August 9, 421 August 15, 421 August
Week 33 in 421 August 16, 421 August 22, 421 August
Week 34 in 421 August 23, 421 August 29, 421 August
Week 35 in 421 August 30, 421 September 5, 421 August / September
Week 36 in 421 September 6, 421 September 12, 421 September
Week 37 in 421 September 13, 421 September 19, 421 September
Week 38 in 421 September 20, 421 September 26, 421 September
Week 39 in 421 September 27, 421 October 3, 421 September / October
Week 40 in 421 October 4, 421 October 10, 421 October
Week 41 in 421 October 11, 421 October 17, 421 October
Week 42 in 421 October 18, 421 October 24, 421 October
Week 43 in 421 October 25, 421 October 31, 421 October
Week 44 in 421 November 1, 421 November 7, 421 November
Week 45 in 421 November 8, 421 November 14, 421 November
Week 46 in 421 November 15, 421 November 21, 421 November
Week 47 in 421 November 22, 421 November 28, 421 November
Week 48 in 421 November 29, 421 December 5, 421 November / December
Week 49 in 421 December 6, 421 December 12, 421 December
Week 50 in 421 December 13, 421 December 19, 421 December
Week 51 in 421 December 20, 421 December 26, 421 December
Week 52 in 421 December 27, 421 January 2, 422 December / January

Calendars 421

January 421
MoTuWeThFrSaSu
Week 53123
Week 145678910
Week 211121314151617
Week 318192021222324
Week 425262728293031
February 421
MoTuWeThFrSaSu
Week 51234567
Week 6891011121314
Week 715161718192021
Week 822232425262728
March 421
MoTuWeThFrSaSu
Week 91234567
Week 10891011121314
Week 1115161718192021
Week 1222232425262728
Week 13293031
April 421
MoTuWeThFrSaSu
Week 131234
Week 14567891011
Week 1512131415161718
Week 1619202122232425
Week 172627282930
May 421
MoTuWeThFrSaSu
Week 1712
Week 183456789
Week 1910111213141516
Week 2017181920212223
Week 2124252627282930
Week 2231
June 421
MoTuWeThFrSaSu
Week 22123456
Week 2378910111213
Week 2414151617181920
Week 2521222324252627
Week 26282930
July 421
MoTuWeThFrSaSu
Week 261234
Week 27567891011
Week 2812131415161718
Week 2919202122232425
Week 30262728293031
August 421
MoTuWeThFrSaSu
Week 301
Week 312345678
Week 329101112131415
Week 3316171819202122
Week 3423242526272829
Week 353031
September 421
MoTuWeThFrSaSu
Week 3512345
Week 366789101112
Week 3713141516171819
Week 3820212223242526
Week 3927282930
October 421
MoTuWeThFrSaSu
Week 39123
Week 4045678910
Week 4111121314151617
Week 4218192021222324
Week 4325262728293031
November 421
MoTuWeThFrSaSu
Week 441234567
Week 45891011121314
Week 4615161718192021
Week 4722232425262728
Week 482930
December 421
MoTuWeThFrSaSu
Week 112345
Week 496789101112
Week 5013141516171819
Week 5120212223242526
Week 522728293031

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Find the week number of a date

How week numbers are counted

Most of the world numbers weeks according to the ISO 8601 standard. A week starts on Monday, and week 1 is the week that contains the first Thursday of the year, which is always the week that contains 4 January.

Week 1 of 421 starts on January 4, 421 and ends on January 10, 421 (ISO 8601, Monday to Sunday). 421 has 52 ISO weeks.

Because of this rule, the first days of January can belong to the last week of the previous year, and the last days of December can belong to week 1 of the next year.

In the United States, weeks usually start on Sunday and week 1 is the week that contains 1 January, so the US week number can differ from the ISO week number.

Frequently Asked Questions (FAQ)

How many weeks does 421 have?

421 has 52 ISO weeks.

When does week 1 of 421 start?

Week 1 of 421 starts on January 4, 421 and ends on January 10, 421 (ISO 8601, Monday to Sunday).

When does the last week of 421 end?

Week 52 of 421 starts on December 27, 421 and ends on January 2, 422 (ISO 8601, Monday to Sunday).

Which years have 53 weeks?

The next years with 53 ISO weeks are 426, 432, 437, 443, 448.

Why do the US and Europe show different week numbers?

Europe follows ISO 8601: weeks start on Monday and week 1 is the week with the first Thursday of the year. In the US, weeks usually start on Sunday and week 1 is the week that contains 1 January, so the two numbers can differ by one.