WhatWeek

Week 53, 2026

Week 53 of 2026 runs from Monday, December 28, 2026 to Sunday, January 3, 2027.

ISO Week 53: 2026-12-28 to 2027-01-03

ISO notation
2026-W53
Start date
2026-12-28
End date
2027-01-03
API example
/api/week-to-date?year=2026&week=53&system=iso
Calendar export
/api/ics/week?year=2026&week=53&system=iso

All 7 days

  • Monday
  • Tuesday
  • Wednesday
  • Thursday
  • Friday
  • Saturday
  • Sunday

Business days this week

Standard Monday-Friday count. Public holidays are not subtracted.

Business days

5

Weekend days

2

Long weekends this week

Long-weekend status depends on a country or region, and no location is selected on this global page. Use Date to Week with a location before planning time off.

December 2026

ISO week numbers in the first column.

View the 2026 calendar
Wk MonTueWedThuFriSatSun
49
50
51
52
53
1

Quarter and day-of-year context

Quarter range
Q4 2026 to Q1 2027
Day-of-year range
Day 362 of 2026 to day 3 of 2027

US-style comparison

This ISO week crosses the simplified Sunday-start US week-year boundary:

  • Week 53 of 2026
  • Week 1 of 2027
  • Week 2 of 2027

Export Week 53

Download Week 53 as an all-day calendar event, or copy the JSON response for apps and automations.

Download .ics 
{
  "year": 2026,
  "week": 53,
  "system": "iso",
  "isoWeek": "2026-W53",
  "weekStarts": "2026-12-28",
  "weekEnds": "2027-01-03",
  "days": [
    {
      "date": "2026-12-28",
      "weekday": 1,
      "name": "Monday",
      "isWeekend": false
    },
    {
      "date": "2026-12-29",
      "weekday": 2,
      "name": "Tuesday",
      "isWeekend": false
    },
    {
      "date": "2026-12-30",
      "weekday": 3,
      "name": "Wednesday",
      "isWeekend": false
    },
    {
      "date": "2026-12-31",
      "weekday": 4,
      "name": "Thursday",
      "isWeekend": false
    },
    {
      "date": "2027-01-01",
      "weekday": 5,
      "name": "Friday",
      "isWeekend": false
    },
    {
      "date": "2027-01-02",
      "weekday": 6,
      "name": "Saturday",
      "isWeekend": true
    },
    {
      "date": "2027-01-03",
      "weekday": 7,
      "name": "Sunday",
      "isWeekend": true
    }
  ]
}

Why 2026 has Week 53

An ISO year has 53 weeks when January 1 is a Thursday, or when a leap year starts on Wednesday. 2026 starts on Thursday, so it has a 53rd ISO week.

Learn about 53-week years