WhatWeek

Fast, ISO-aware week number tool

What Week Is It?

It is ISO Week 26 of 2026.

Based on Asia/Shanghai.

WEEK CONSOLE

Week 26

ISO week 2026-W26
Date range
Monday, June 22, 2026 – Sunday, June 28, 2026
Time zone
Asia/Shanghai
  • US-style Week 26
  • Remaining 27 ISO weeks remain
  • 49% ISO year 49% of the ISO year has elapsed
    ISO year progress 49% elapsed
  • Year length 2026 has 53 ISO weeks
Week at a glance 2026-W26
  1. Mon 22
  2. Tue 23
  3. Wed 24
  4. Thu 25
  5. Fri 26
  6. Sat 27
  7. Sun 28

Find the current ISO week number, date range, US-style week number, and verified holiday context when available.

  • ISO-aware
  • Time zone aware
  • US-style comparison

Quick converter

Convert a date to an ISO or US-style week number.

Type any IANA time zone, such as Europe/Paris or America/Los_Angeles.
Week system

ISO vs US-style week numbers

The same date can belong to different week numbers depending on the week system.

ISO week

2026-W26

ISO guide

Weeks start on Monday. Week 1 contains the first Thursday of the year.

Mon Tue Wed Thu Fri Sat Sun

US-style week

Week 26

US-style guide

Weeks start on Sunday. Week 1 contains January 1.

Sun Mon Tue Wed Thu Fri Sat

Holiday context: China

Official public holiday context for China. This holiday panel uses Asia/Shanghai.

Change country

Holiday data checked for this week

Official holiday data is verified for China 2026.

Planning summary

5 business days · 2 non-working days · 0 verified public holidays

  • Check regional holidays before scheduling deadlines.
  • Business-day counts may vary by country and region.

May 2026

ISO week numbers in the first column.

View full 2026 calendar
Wk MonTueWedThuFriSatSun
18
19
20
21
22
23

Jump from the current week answer into converters, calendars, and developer references.

Explore the API

Why week numbers differ

ISO weeks start on Monday and define Week 1 as the week containing the first Thursday of the year. US-style weeks usually start on Sunday and count the week containing January 1 as Week 1. Around New Year, these systems often show different week years and week numbers.

FAQ

What is the current ISO week?

The current ISO week is 2026-W26, based on Asia/Shanghai and personalized to your browser timezone when available.

Does 2026 have 53 ISO weeks?

Yes. 2026 has 53 ISO weeks, and Week 53 runs from Monday, December 28, 2026 to Sunday, January 3, 2027.

Why is the US-style week number different?

US-style week numbering starts weeks on Sunday and counts Week 1 as the week containing January 1, so it can differ from ISO around New Year.