US Week Number
Current US-style week number
The current US-style week number is Week 33 of 2026, based on America/New_York.
Current ISO comparison
The current ISO week is 2026-W33. ISO and US-style numbers differ because they use different week starts and Week 1 rules.
Sunday-start week calendar
WhatWeek uses a simplified US-style week number where weeks start on Sunday and Week 1 contains January 1.
| System | Week starts | Week 1 rule |
|---|---|---|
| US-style in WhatWeek | Sunday | The week containing January 1 |
| ISO | Monday | The week containing the first Thursday |
US federal holidays this week
This section covers U.S. federal holidays only. State and local holidays can differ.
The verified 2026 federal calendar contains no federal holiday in this US-style week.
For 2026, WhatWeek uses the official U.S. Office of Personnel Management federal holiday calendar.
Why US-style and ISO week numbers differ
A date near New Year can have different week numbers because Sunday-start and Monday-start systems place the same day into different week ranges. The first week of the year is also defined differently.
- 2026-01-01 is in Week 1 in both systems, but the surrounding date range differs.
- 2026-05-03 is a Sunday, so it starts a new US-style week while it ends ISO Week 18.
- 2027-01-03 is still ISO 2026-W53, but it is already a US-style week in calendar year 2027.
Convert date to US-style week number
Use the date to week converter and choose the US-style week system.
US-style week calendar by year
Start with the 2026 calendar with week numbers to compare ISO ranges with Sunday-start planning weeks.