Week numbers 401

401 has 52 ISO weeks. Week 1: Jan 1 – 7 · Week 52: Dec 24 – 30

401 at a glance

Weeks in 40152
Week 1January 1, 401 – January 7, 401
Week 52December 24, 401 – December 30, 401
Days in 401365
Leap yearNo

All Weeks in 401

Week From To Month
Week 1 in 401 January 1, 401 January 7, 401 January
Week 2 in 401 January 8, 401 January 14, 401 January
Week 3 in 401 January 15, 401 January 21, 401 January
Week 4 in 401 January 22, 401 January 28, 401 January
Week 5 in 401 January 29, 401 February 4, 401 January / February
Week 6 in 401 February 5, 401 February 11, 401 February
Week 7 in 401 February 12, 401 February 18, 401 February
Week 8 in 401 February 19, 401 February 25, 401 February
Week 9 in 401 February 26, 401 March 4, 401 February / March
Week 10 in 401 March 5, 401 March 11, 401 March
Week 11 in 401 March 12, 401 March 18, 401 March
Week 12 in 401 March 19, 401 March 25, 401 March
Week 13 in 401 March 26, 401 April 1, 401 March / April
Week 14 in 401 April 2, 401 April 8, 401 April
Week 15 in 401 April 9, 401 April 15, 401 April
Week 16 in 401 April 16, 401 April 22, 401 April
Week 17 in 401 April 23, 401 April 29, 401 April
Week 18 in 401 April 30, 401 May 6, 401 April / May
Week 19 in 401 May 7, 401 May 13, 401 May
Week 20 in 401 May 14, 401 May 20, 401 May
Week 21 in 401 May 21, 401 May 27, 401 May
Week 22 in 401 May 28, 401 June 3, 401 May / June
Week 23 in 401 June 4, 401 June 10, 401 June
Week 24 in 401 June 11, 401 June 17, 401 June
Week 25 in 401 June 18, 401 June 24, 401 June
Week 26 in 401 June 25, 401 July 1, 401 June / July
Week 27 in 401 July 2, 401 July 8, 401 July
Week 28 in 401 July 9, 401 July 15, 401 July
Week 29 in 401 July 16, 401 July 22, 401 July
Week 30 in 401 July 23, 401 July 29, 401 July
Week 31 in 401 July 30, 401 August 5, 401 July / August
Week 32 in 401 August 6, 401 August 12, 401 August
Week 33 in 401 August 13, 401 August 19, 401 August
Week 34 in 401 August 20, 401 August 26, 401 August
Week 35 in 401 August 27, 401 September 2, 401 August / September
Week 36 in 401 September 3, 401 September 9, 401 September
Week 37 in 401 September 10, 401 September 16, 401 September
Week 38 in 401 September 17, 401 September 23, 401 September
Week 39 in 401 September 24, 401 September 30, 401 September
Week 40 in 401 October 1, 401 October 7, 401 October
Week 41 in 401 October 8, 401 October 14, 401 October
Week 42 in 401 October 15, 401 October 21, 401 October
Week 43 in 401 October 22, 401 October 28, 401 October
Week 44 in 401 October 29, 401 November 4, 401 October / November
Week 45 in 401 November 5, 401 November 11, 401 November
Week 46 in 401 November 12, 401 November 18, 401 November
Week 47 in 401 November 19, 401 November 25, 401 November
Week 48 in 401 November 26, 401 December 2, 401 November / December
Week 49 in 401 December 3, 401 December 9, 401 December
Week 50 in 401 December 10, 401 December 16, 401 December
Week 51 in 401 December 17, 401 December 23, 401 December
Week 52 in 401 December 24, 401 December 30, 401 December

Calendars 401

January 401
MoTuWeThFrSaSu
Week 11234567
Week 2891011121314
Week 315161718192021
Week 422232425262728
Week 5293031
February 401
MoTuWeThFrSaSu
Week 51234
Week 6567891011
Week 712131415161718
Week 819202122232425
Week 9262728
March 401
MoTuWeThFrSaSu
Week 91234
Week 10567891011
Week 1112131415161718
Week 1219202122232425
Week 13262728293031
April 401
MoTuWeThFrSaSu
Week 131
Week 142345678
Week 159101112131415
Week 1616171819202122
Week 1723242526272829
Week 1830
May 401
MoTuWeThFrSaSu
Week 18123456
Week 1978910111213
Week 2014151617181920
Week 2121222324252627
Week 2228293031
June 401
MoTuWeThFrSaSu
Week 22123
Week 2345678910
Week 2411121314151617
Week 2518192021222324
Week 26252627282930
July 401
MoTuWeThFrSaSu
Week 261
Week 272345678
Week 289101112131415
Week 2916171819202122
Week 3023242526272829
Week 313031
August 401
MoTuWeThFrSaSu
Week 3112345
Week 326789101112
Week 3313141516171819
Week 3420212223242526
Week 352728293031
September 401
MoTuWeThFrSaSu
Week 3512
Week 363456789
Week 3710111213141516
Week 3817181920212223
Week 3924252627282930
October 401
MoTuWeThFrSaSu
Week 401234567
Week 41891011121314
Week 4215161718192021
Week 4322232425262728
Week 44293031
November 401
MoTuWeThFrSaSu
Week 441234
Week 45567891011
Week 4612131415161718
Week 4719202122232425
Week 482627282930
December 401
MoTuWeThFrSaSu
Week 212
Week 493456789
Week 5010111213141516
Week 5117181920212223
Week 5224252627282930
Week 131

Download Calendar in printable A4 PDF

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 401 starts on January 1, 401 and ends on January 7, 401 (ISO 8601, Monday to Sunday). 401 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 401 have?

401 has 52 ISO weeks.

When does week 1 of 401 start?

Week 1 of 401 starts on January 1, 401 and ends on January 7, 401 (ISO 8601, Monday to Sunday).

When does the last week of 401 end?

Week 52 of 401 starts on December 24, 401 and ends on December 30, 401 (ISO 8601, Monday to Sunday).

Which years have 53 weeks?

The next years with 53 ISO weeks are 404, 409, 415, 420, 426.

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.