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Week Number Calculator

Calculate current week numbers instantly. Supports ISO 8601 and US standards. Find week start/end dates, view full-year directory directories, and query dates.

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📅 Date to Week Number Calculator

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ISO 8601 Week Number (Standard)
Week 31
Thursday, July 30, 2026
US Standard Week
Week 31
Starts Sunday
ISO Week Range
Mon, Jul 27, 2026
to
Sun, Aug 2, 2026
US Week Range
Sun, Jul 26, 2026
to
Sat, Aug 1, 2026
Year Progress
57.8%
3 days left in week
Quick Benchmarks & Presets:

🔢 Week to Date Range Resolver

ISO Standard Range
Mon, Jul 27, 2026
to
Sun, Aug 2, 2026
Starts Monday, Ends Sunday
US Standard Range
Sun, Jul 26, 2026
to
Sat, Aug 1, 2026
Starts Sunday, Ends Saturday

📅 Year Week Directory

Week NumberStart Date (Mon)End Date (Sun)
Week 1 Mon, Dec 29, 2025Sun, Jan 4, 2026
Week 2 Mon, Jan 5, 2026Sun, Jan 11, 2026
Week 3 Mon, Jan 12, 2026Sun, Jan 18, 2026
Week 4 Mon, Jan 19, 2026Sun, Jan 25, 2026
Week 5 Mon, Jan 26, 2026Sun, Feb 1, 2026
Week 6 Mon, Feb 2, 2026Sun, Feb 8, 2026
Week 7 Mon, Feb 9, 2026Sun, Feb 15, 2026
Week 8 Mon, Feb 16, 2026Sun, Feb 22, 2026
Week 9 Mon, Feb 23, 2026Sun, Mar 1, 2026
Week 10 Mon, Mar 2, 2026Sun, Mar 8, 2026
Week 11 Mon, Mar 9, 2026Sun, Mar 15, 2026
Week 12 Mon, Mar 16, 2026Sun, Mar 22, 2026
Week 13 Mon, Mar 23, 2026Sun, Mar 29, 2026
Week 14 Mon, Mar 30, 2026Sun, Apr 5, 2026
Week 15 Mon, Apr 6, 2026Sun, Apr 12, 2026
Week 16 Mon, Apr 13, 2026Sun, Apr 19, 2026
Week 17 Mon, Apr 20, 2026Sun, Apr 26, 2026
Week 18 Mon, Apr 27, 2026Sun, May 3, 2026
Week 19 Mon, May 4, 2026Sun, May 10, 2026
Week 20 Mon, May 11, 2026Sun, May 17, 2026
Week 21 Mon, May 18, 2026Sun, May 24, 2026
Week 22 Mon, May 25, 2026Sun, May 31, 2026
Week 23 Mon, Jun 1, 2026Sun, Jun 7, 2026
Week 24 Mon, Jun 8, 2026Sun, Jun 14, 2026
Week 25 Mon, Jun 15, 2026Sun, Jun 21, 2026
Week 26 Mon, Jun 22, 2026Sun, Jun 28, 2026
Week 27 Mon, Jun 29, 2026Sun, Jul 5, 2026
Week 28 Mon, Jul 6, 2026Sun, Jul 12, 2026
Week 29 Mon, Jul 13, 2026Sun, Jul 19, 2026
Week 30 Mon, Jul 20, 2026Sun, Jul 26, 2026
Week 31 Current WeekMon, Jul 27, 2026Sun, Aug 2, 2026
Week 32 Mon, Aug 3, 2026Sun, Aug 9, 2026
Week 33 Mon, Aug 10, 2026Sun, Aug 16, 2026
Week 34 Mon, Aug 17, 2026Sun, Aug 23, 2026
Week 35 Mon, Aug 24, 2026Sun, Aug 30, 2026
Week 36 Mon, Aug 31, 2026Sun, Sep 6, 2026
Week 37 Mon, Sep 7, 2026Sun, Sep 13, 2026
Week 38 Mon, Sep 14, 2026Sun, Sep 20, 2026
Week 39 Mon, Sep 21, 2026Sun, Sep 27, 2026
Week 40 Mon, Sep 28, 2026Sun, Oct 4, 2026
Week 41 Mon, Oct 5, 2026Sun, Oct 11, 2026
Week 42 Mon, Oct 12, 2026Sun, Oct 18, 2026
Week 43 Mon, Oct 19, 2026Sun, Oct 25, 2026
Week 44 Mon, Oct 26, 2026Sun, Nov 1, 2026
Week 45 Mon, Nov 2, 2026Sun, Nov 8, 2026
Week 46 Mon, Nov 9, 2026Sun, Nov 15, 2026
Week 47 Mon, Nov 16, 2026Sun, Nov 22, 2026
Week 48 Mon, Nov 23, 2026Sun, Nov 29, 2026
Week 49 Mon, Nov 30, 2026Sun, Dec 6, 2026
Week 50 Mon, Dec 7, 2026Sun, Dec 13, 2026
Week 51 Mon, Dec 14, 2026Sun, Dec 20, 2026
Week 52 Mon, Dec 21, 2026Sun, Dec 27, 2026
Week 53 Mon, Dec 28, 2026Sun, Jan 3, 2027

Overview & Capabilities

Find the current week number or resolve the week dates for any year. Perfect for logisticians, remote managers planning sprints, calendar audits, and accounting cycles.

Tutorial

How to Use

01
Select any date to instantly compute its corresponding ISO-8601 standard week and US calendar week.
02
Use the visual card to compare Monday-to-Sunday and Sunday-to-Saturday ranges.
03
Enter a year and week number in the resolver to calculate the start and end dates of that week.
04
Type natural queries like "week 42" or "today" into the smart power search bar.
05
Audit the full year directory in the scrollable table to match dates with weeks.
Capabilities

Key Features

**Dual Standard Compatibility**: Supports both ISO-8601 (Monday start) and US/Canada (Sunday start) week rules.
**Interactive Resolver**: Computes calendar boundary dates for any week of any year in one click.
**NLP Smart Query**: Resolves natural phrases like "Halloween 2026" or "week 12 2025" dynamically.
**Full Year Directory Directory**: Lists all weeks of any selected year with highlights for the active current week.
**Progress Metrics**: Shows the percentage of the year elapsed and exact days remaining in the active week.
Applications

Common Use Cases

Sprint planning and scrum agile project cycles
Logistics shipments, tracking cargo delivery cycles
Fiscal accounting cycles and salary payroll weeks
Pregnancy week calendars and developmental benchmarks
School term calendars and semester syllabus planning
Data analysis sorting timestamps into weeks
Guidance

Tips & Best Practices

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In the ISO 8601 standard, Week 1 is defined as the week containing the first Thursday of the year.
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Under the US standard, Week 1 always starts on Sunday and contains January 1st.
Ecosystem

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Answers

Frequently Asked Questions

Q What week number is it today?

The current week number depends on today's date and the calendar standard you use. Use the Today button on this page to load the exact week number instantly.

Q How does the ISO 8601 week number standard work?

ISO 8601 defines the week as starting on Monday. Week 01 of any year is the week that contains the first Thursday of that year (which is equivalent to the week containing January 4th).

Q How does the US week number standard differ from ISO?

Under the US standard, weeks start on Sunday. Week 1 is defined as the week containing January 1st, regardless of what day of the week it falls on.

Q Can a year have 53 weeks?

Yes, years that start on a Thursday (or a Wednesday in leap years) contain 53 weeks under the ISO 8601 standard.

Q How do you calculate the week number mathematically?

To calculate the ISO week number, convert the date to UTC, find the closest Thursday, find the first day of that year, compute the difference in days, and divide by 7.