Week Number Calculator
Get the ISO week number for any date.
Last updated: July 17, 2026
The ISO week number identifies which of the 52 or 53 weeks of the year a given date falls in, with each week starting on Monday. Enter a date below to find its week number.
Week number: 30.
Enter values and calculate
Fill in the form above and press Calculate to see your result.
How this calculator works
Utility calculators answer a single calendar or time question—such as whether a year is a leap year, how many days a month has, which week number applies, or how to convert Unix timestamps.
Each tool uses the same accurate date engine as full calculators but focuses on one result so you get a fast, authoritative answer.
Worked example
Checking 2028 confirms it is a leap year with 366 days, which affects interest accrual, contract lengths, and February payroll.
Converting a Unix timestamp from a server log into a readable date helps developers debug events without leaving the browser.
Practical use cases
Spreadsheet builders, developers, students, and planners use utilities for quick facts that feed into larger date calculations.
Week-number and quarter tools align reporting periods. Days-in-month helpers validate billing cycles. Leap-year checks prevent off-by-one errors in annual schedules.
When utilities are not enough, open the Date Calculators category for add, subtract, and compare tools.
Frequently asked questions
These tools answer focused calendar questions such as leap years, days in a month, week numbers, quarters, and Unix timestamp conversions.
Yes. All utilities follow standard Gregorian calendar rules used in most business and personal planning.
Use utilities when you need a single fact—like whether a year is a leap year—rather than adding, subtracting, or comparing two dates.
Yes. Convert between Unix epoch seconds and readable dates for logs, APIs, and database timestamps.
Related calculations
Written & Reviewed by
DateCalx Team
Editorial Team
The DateCalx Team researches, builds, tests, and reviews every calculator to ensure accurate, reliable, and easy-to-understand date and time calculations. Our goal is to provide fast, trustworthy tools for everyday personal, educational, and professional use.
Last reviewed: July 17, 2026
Learn more in our About, Editorial Policy, and Methodology pages, or contact the DateCalx Team.