Week numbers 521

521 has 52 ISO weeks. Week 1: Dec 30, 520 – Jan 5, 521 · Week 52: Dec 22 – 28

521 at a glance

Weeks in 52152
Week 1December 30, 520 – January 5, 521
Week 52December 22, 521 – December 28, 521
Days in 521365
Leap yearNo

All Weeks in 521

Week From To Month
Week 1 in 521 December 30, 520 January 5, 521 December / January
Week 2 in 521 January 6, 521 January 12, 521 January
Week 3 in 521 January 13, 521 January 19, 521 January
Week 4 in 521 January 20, 521 January 26, 521 January
Week 5 in 521 January 27, 521 February 2, 521 January / February
Week 6 in 521 February 3, 521 February 9, 521 February
Week 7 in 521 February 10, 521 February 16, 521 February
Week 8 in 521 February 17, 521 February 23, 521 February
Week 9 in 521 February 24, 521 March 2, 521 February / March
Week 10 in 521 March 3, 521 March 9, 521 March
Week 11 in 521 March 10, 521 March 16, 521 March
Week 12 in 521 March 17, 521 March 23, 521 March
Week 13 in 521 March 24, 521 March 30, 521 March
Week 14 in 521 March 31, 521 April 6, 521 March / April
Week 15 in 521 April 7, 521 April 13, 521 April
Week 16 in 521 April 14, 521 April 20, 521 April
Week 17 in 521 April 21, 521 April 27, 521 April
Week 18 in 521 April 28, 521 May 4, 521 April / May
Week 19 in 521 May 5, 521 May 11, 521 May
Week 20 in 521 May 12, 521 May 18, 521 May
Week 21 in 521 May 19, 521 May 25, 521 May
Week 22 in 521 May 26, 521 June 1, 521 May / June
Week 23 in 521 June 2, 521 June 8, 521 June
Week 24 in 521 June 9, 521 June 15, 521 June
Week 25 in 521 June 16, 521 June 22, 521 June
Week 26 in 521 June 23, 521 June 29, 521 June
Week 27 in 521 June 30, 521 July 6, 521 June / July
Week 28 in 521 July 7, 521 July 13, 521 July
Week 29 in 521 July 14, 521 July 20, 521 July
Week 30 in 521 July 21, 521 July 27, 521 July
Week 31 in 521 July 28, 521 August 3, 521 July / August
Week 32 in 521 August 4, 521 August 10, 521 August
Week 33 in 521 August 11, 521 August 17, 521 August
Week 34 in 521 August 18, 521 August 24, 521 August
Week 35 in 521 August 25, 521 August 31, 521 August
Week 36 in 521 September 1, 521 September 7, 521 September
Week 37 in 521 September 8, 521 September 14, 521 September
Week 38 in 521 September 15, 521 September 21, 521 September
Week 39 in 521 September 22, 521 September 28, 521 September
Week 40 in 521 September 29, 521 October 5, 521 September / October
Week 41 in 521 October 6, 521 October 12, 521 October
Week 42 in 521 October 13, 521 October 19, 521 October
Week 43 in 521 October 20, 521 October 26, 521 October
Week 44 in 521 October 27, 521 November 2, 521 October / November
Week 45 in 521 November 3, 521 November 9, 521 November
Week 46 in 521 November 10, 521 November 16, 521 November
Week 47 in 521 November 17, 521 November 23, 521 November
Week 48 in 521 November 24, 521 November 30, 521 November
Week 49 in 521 December 1, 521 December 7, 521 December
Week 50 in 521 December 8, 521 December 14, 521 December
Week 51 in 521 December 15, 521 December 21, 521 December
Week 52 in 521 December 22, 521 December 28, 521 December

Calendars 521

January 521
MoTuWeThFrSaSu
Week 112345
Week 26789101112
Week 313141516171819
Week 420212223242526
Week 52728293031
February 521
MoTuWeThFrSaSu
Week 512
Week 63456789
Week 710111213141516
Week 817181920212223
Week 92425262728
March 521
MoTuWeThFrSaSu
Week 912
Week 103456789
Week 1110111213141516
Week 1217181920212223
Week 1324252627282930
Week 1431
April 521
MoTuWeThFrSaSu
Week 14123456
Week 1578910111213
Week 1614151617181920
Week 1721222324252627
Week 18282930
May 521
MoTuWeThFrSaSu
Week 181234
Week 19567891011
Week 2012131415161718
Week 2119202122232425
Week 22262728293031
June 521
MoTuWeThFrSaSu
Week 221
Week 232345678
Week 249101112131415
Week 2516171819202122
Week 2623242526272829
Week 2730
July 521
MoTuWeThFrSaSu
Week 27123456
Week 2878910111213
Week 2914151617181920
Week 3021222324252627
Week 3128293031
August 521
MoTuWeThFrSaSu
Week 31123
Week 3245678910
Week 3311121314151617
Week 3418192021222324
Week 3525262728293031
September 521
MoTuWeThFrSaSu
Week 361234567
Week 37891011121314
Week 3815161718192021
Week 3922232425262728
Week 402930
October 521
MoTuWeThFrSaSu
Week 4012345
Week 416789101112
Week 4213141516171819
Week 4320212223242526
Week 442728293031
November 521
MoTuWeThFrSaSu
Week 4412
Week 453456789
Week 4610111213141516
Week 4717181920212223
Week 4824252627282930
December 521
MoTuWeThFrSaSu
Week 491234567
Week 50891011121314
Week 5115161718192021
Week 5222232425262728
Week 1293031

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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 521 starts on December 30, 520 and ends on January 5, 521 (ISO 8601, Monday to Sunday). 521 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 521 have?

521 has 52 ISO weeks.

When does week 1 of 521 start?

Week 1 of 521 starts on December 30, 520 and ends on January 5, 521 (ISO 8601, Monday to Sunday).

When does the last week of 521 end?

Week 52 of 521 starts on December 22, 521 and ends on December 28, 521 (ISO 8601, Monday to Sunday).

Which years have 53 weeks?

The next years with 53 ISO weeks are 522, 528, 533, 539, 544.

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.