Week Number Calculator - ISO 8601 Week of Year

Calculators / Date Calculators / Week Number Calculator

Calculate Week Number

Enter any date to find out its ISO 8601 week number and detailed week information. The calculation follows the international standard where week 1 is the first week with at least 4 days in the new year.

Most Popular Date Calculators

Time Difference Calculator
Day of the Week Calculator
Date Difference Calculator
Business Days Calculator
Add Days to Date
New
Add Days to Date Start from any date and move forwards or backwards by days, weeks, months or years - with a business-day mode that skips weekends.
View Page
Popular Today
Day of the Week Calculator Free day of the week calculator: find out which weekday any date falls on - past or future - handy for birthdays, events and historical dates.
View Page

Related Date Calculators

Age Calculator Free age calculator: enter your birth date to see your exact age in years, months, days, hours and minutes, plus the countdown to your next birthday.
Date Difference Calculator Free date difference calculator: find the exact time between two dates in years, months, days and weeks, and see how many working days fall in between.
Day of the Week Calculator Free day of the week calculator: find out which weekday any date falls on - past or future - handy for birthdays, events and historical dates.
Business Days Calculator Free business days calculator: count the working days between two dates, weekends excluded - useful for deadlines, delivery dates and project planning.
Pregnancy Calculator Free pregnancy calculator: work out your due date, current week and trimester from your last menstrual period, with the estimated conception date.

Other Calculators You May Like

Loan Calculator Free loan calculator for monthly payment, total interest and total cost. Works for personal, auto and other fixed-rate loans, with a full amortization table.
Partially Amortized Loan Calculator Free balloon loan calculator: enter amount, rate, amortisation term and actual term to see the monthly payment, balloon balance and total cost.
Compound Interest Calculator Free compound interest calculator: see the final balance, total interest earned and year-by-year growth for any compounding frequency and regular deposits.
Break-Even Calculator Free break-even calculator: find how many units you must sell to cover costs, with break-even revenue, contribution margin and profit at any volume.
ROI Calculator Free ROI calculator: enter the amount invested and returned to see your ROI percentage, net profit, annualised return and payback period.