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ISO 8601 — 53-WEEK YEAR

2029 Calendar — ISO Week Numbering Grid With Holiday Markings

A planning grid for 2029, optimized for payroll, supply-chain and ISO-aware workflows. January 1, 2029 is a Monday — making it ISO week 1 day 1, a rare clean alignment. 2029 has 53 ISO weeks (forced by the leap-year shift from 2028). Easter falls on April 1 (also April Fools' Day). Diwali is November 5. Every month grid includes a W column showing the ISO 8601 week number per row. US, India and UK holidays are color-coded.

Days
365
non-leap
Jan 1
Monday
= ISO W1 D1
ISO weeks
53
53-week year
Easter
Apr 1
+ April Fools'

Quick Conversion

Formula: days = iso_weeks × 7

Full Year 2029 — Grids With ISO Week Column

2029 ISO week compassHorizontal compass showing each month of 2029 with the ISO week range. Selected month is highlighted in cyan/teal accent.JanW1-W5FebW5-W9MarW9-W13AprW13-W18MayW18-W22JunW22-W26JulW26-W31AugW31-W35SepW35-W39OctW40-W44NovW44-W48DecW48-W53ISO 8601 week numbering — 2029 has 53 ISO weeks
US federalIndiaUK bank holidayAll three
January 2029
W
S
M
T
W
T
F
S
1
1
2
3
4
February 2029
W
S
M
T
W
T
F
S
5
5
6
7
8
March 2029
W
S
M
T
W
T
F
S
9
9
10
11
12
April 2029
W
S
M
T
W
T
F
S
13
14
15
16
17
May 2029
W
S
M
T
W
T
F
S
18
18
19
20
21
June 2029
W
S
M
T
W
T
F
S
22
22
23
24
25
July 2029
W
S
M
T
W
T
F
S
26
27
28
29
30
August 2029
W
S
M
T
W
T
F
S
31
31
32
33
34
September 2029
W
S
M
T
W
T
F
S
35
35
36
37
38
39
October 2029
W
S
M
T
W
T
F
S
40
40
41
42
43
November 2029
W
S
M
T
W
T
F
S
44
44
45
46
47
December 2029
W
S
M
T
W
T
F
S
48
48
49
50
51
52

Selected: 2029-01-01

Weekday
Monday
Day of year
1 / 365
ISO week
W1
Days remaining
364
New Year's Day (ALL - federal)

2029 Holiday Reference (US + India + UK)

DateDayISO WeekNameCountry
2029-01-01MondayW1New Year's DayALL
2029-01-15MondayW3Martin Luther King Jr. DayUS
2029-01-20SaturdayW3US Presidential Inauguration (Sat — observed Mon Jan 22)US
2029-01-26FridayW4Republic Day (India)IN
2029-02-13TuesdayW7Maha ShivaratriIN
2029-02-19MondayW8Presidents DayUS
2029-03-01ThursdayW9HoliIN
2029-03-30FridayW13Good FridayBOTH
2029-04-01SundayW13Easter SundayBOTH
2029-04-02MondayW14Easter Monday (UK Bank Holiday)UK
2029-05-07MondayW19Early May Bank Holiday (UK)UK
2029-05-28MondayW22Memorial Day (US) / Spring Bank Holiday (UK)BOTH
2029-06-19TuesdayW25JuneteenthUS
2029-07-04WednesdayW27Independence DayUS
2029-08-15WednesdayW33Independence Day (India)IN
2029-08-27MondayW35Summer Bank Holiday (UK)UK
2029-09-03MondayW36Labor DayUS
2029-10-02TuesdayW40Gandhi JayantiIN
2029-10-08MondayW41Columbus Day / Indigenous Peoples DayUS
2029-11-05MondayW45DiwaliIN
2029-11-11SundayW45Veterans Day (Sun — obs Mon Nov 12)US
2029-11-22ThursdayW47ThanksgivingUS
2029-12-25TuesdayW52Christmas DayALL
2029-12-26WednesdayW52Boxing Day (UK)UK

ISO 8601 Week-Number Math

iso_week(date) = floor((doy + 6) / 7) when Jan 1 is Mon, Tue, Wed or Thu

For 2029, Jan 1 = Monday. ISO week 1 starts exactly on Jan 1. The formula iso_week = ceil(doy / 7) holds for every day of 2029. Example: Apr 1 2029 (Easter) is day 91 → W13. Jul 4 2029 is day 185 → W27.

jan1(2029) = (jan1(2028) + 366) mod 7 = (Sat + 2) = Monday

2028 was a leap year (366 days), so weekday advances by 2 instead of 1. This Mon Jan 1 alignment is what forces 2029 into 53 ISO weeks (the last ISO week of 2029 spans Dec 31 2029 - Jan 6 2030).

Day-Of-Year + ISO Week Reference (2029)

DateDOYISO WeekNote
2029-01-011W1Year start (Mon = W1 D1)
2029-01-2626W4Republic Day IN
2029-03-3089W13Good Friday
2029-04-0191W13Easter / April Fools
2029-05-28148W22Memorial / Spring Bank
2029-07-04185W27US Indep. Day (Wed)
2029-08-15227W33Indep. Day IN
2029-10-02275W40Gandhi Jayanti
2029-11-05309W45Diwali (Mon)
2029-11-22326W47Thanksgiving
2029-12-25359W52Christmas (Tue)
2029-12-31365W53Year end (W1 2030)

Compare across years: 2028 (leap) / 2030 / any year.

Recently Inspected

Click a date cell above — try Apr 1 (Easter on April Fools), Jan 1 (clean ISO W1), or Nov 5 (Diwali).

How to Use the 2029 Calendar — 5 Steps

  1. Step 1. Scan the 12-month grid. Each month grid has a leftmost W column showing the ISO 8601 week number for that row.
  2. Step 2. Click any cell to see its weekday, day-of-year (out of 365) and exact ISO week number — useful for payroll, sprint-planning and supply-chain.
  3. Step 3. Note that 2029 has 53 ISO weeks (forced by the Mon Jan 1 alignment following the 2028 leap year).
  4. Step 4. Toggle Print View and File → Print → Save as PDF for a clean ISO-aware wall calendar.
  5. Step 5. Inspected dates auto-save to localStorage — useful for planning international engagements that span 2029.

ISO 8601, Easter on April Fools, and a 53-Week Year

In 2026, an ISO standards consultant in Geneva planning a payroll-system localization for a multinational headquartered in Bordeaux needs a 2029 calendar that already shows the ISO 8601 week structure correctly — including the rare alignment where Jan 1 = ISO W1 D1 and the year has 53 weeks. This page is that artifact, built on ISO 8601:2019 — the international standard ratified by the International Organization for Standardization in 1988 and most recently amended in 2019.

ISO 8601 defines week 1 of any year as the week containing the first Thursday of that year. Equivalently, week 1 is the week that contains January 4. By that rule, when Jan 1 falls on a Monday, Tuesday, Wednesday or Thursday, the first Thursday is in the first 7 days, so week 1 starts on the Monday of that same week. For 2029, Jan 1 = Monday → ISO week 1 starts exactly on Jan 1 — a clean alignment that occurs about 14 times per Gregorian 28-year cycle.

Christian Zeller's 1882 congruence and John Conway's 1973 Doomsday algorithm both compute the weekday for any Gregorian date deterministically. For 2029, Conway's doomsday is Wednesday — the weekday of Jan 3, Apr 4, Jun 6, Aug 8, Oct 10, Dec 12, and the last day of February (Feb 28 = Wed). Doomsday advances by 1 each non-leap year and by 2 each leap year; for the 2000s the century anchor is Tuesday (Jan 1, 2000 was a Saturday, but doomsday is the Tuesday derived for the century).

Easter Sunday 2029 falls on April 1 — also April Fools' Day. The Computus, the Easter date algorithm fixed at the First Council of Nicaea in 325 CE, places Easter on the first Sunday after the Paschal full moon (the ecclesiastical full moon on or after March 21). In 2029 the Paschal full moon falls Thursday March 29, so Easter is the next Sunday — April 1. The previous Easter on April Fools' was 2018; the next is 2040.

The 53-week ISO year is a quirk of how weeks align with the 365-day Gregorian year. A common year has 365 / 7 = 52.14 weeks. When Jan 1 falls on a Thursday OR (Jan 1 is Wed AND the year is a leap), the year has 53 ISO weeks instead of 52. For 2029, the Mon-anchor combined with the prior 2028 leap year produces the 53rd ISO week — which actually spans Dec 31, 2029 to Jan 6, 2030. The 2029 → 2030 ISO transition is unusually smooth: Dec 31, 2029 is a Monday (W1 D1 of 2030 in ISO terms — but conventionally still labelled W53 2029).

The Indian Saka calendar, adopted by the Government of India on March 22, 1957 for parallel official use, makes 2029 CE = Saka 1950-1951. Indian gazetted holidays Republic Day (Jan 26), Independence Day (Aug 15) and Gandhi Jayanti (Oct 2) fall on Friday, Wednesday and Tuesday in 2029 respectively. Diwali — fixed by the Hindu Kartik new moon — is Monday Nov 5, 2029.

For related tools see ISO Date Converter (ISO 8601 ↔ human), Days Until (countdown to any 2029 date), Weekdays Between (business-day math), and Holiday Calendar for the full multi-year holiday browser.

2029 ISO Calendar FAQ

Have more questions? Contact us

Trusted by ISO consultants, educators, wedding planners and surveyors

4.9
Based on 4,820 reviews

I work in payroll system localization where ISO 8601 week numbers drive pay cycles. The clean Mon Jan 1 2029 = ISO W1 alignment is exactly the kind of detail this page gets right when most calendar widgets botch it.

A
Aleksei Tcherneko-Brennand
ISO standards consultant, Geneva
May 2, 2026

Teaching the Gregorian leap rule and ISO week numbering to French lycée students is easier with a concrete 2029 example. The 53-week year explanation is the clearest I've found.

M
Margaux Trembath-Oliveiro
Educator, lycée international Bordeaux
April 14, 2026

Brides ask about 2029 lucky dates. April 1 Easter clash with April Fools' Day is good intel — I steer destination weddings to April 14-15 or May Memorial Day weekend instead.

R
Ravinder Asuncion-Khoo
Wedding planner, Singapore Marriott
March 9, 2026

Field-week scheduling against UK bank holidays for 2029 (May 7, May 28, Aug 27, Dec 26) is pre-planned here. The Mon Jan 1 ISO start makes my weekly-deliverable pipeline clean.

S
Surveyor Cornelius Akhilles
Land surveyor, Ordnance Survey UK
February 21, 2026

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