Weeks Between Dates
Total Weeks
0.00
Total Days
0
Complete Weeks
0 weeks + 0 days
Weekdays
0
Weekends
0
Business Weeks
0.00
Pick start and end dates to begin.
Date Planning
Week Calculator with Week Number Tools
Calculate weeks between two dates, check ISO week numbers, and add or subtract weeks to plan project timelines faster.
Week Number Finder
ISO Week
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Day of Year
-
Week Start
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Week End
-
Add or Subtract Weeks (New)
Result Date
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Result ISO Week
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How Week Calculations Work
The week difference tool calculates total days between selected dates and converts it into weeks and remaining days. It also counts weekdays and weekend days so you can estimate business working periods.
ISO week numbers follow a standard where Week 1 is the week containing the first Thursday of the year. This is commonly used in business reporting and planning.
The new week offset tool helps you jump forward or backward by any number of weeks from a base date, useful for release planning, payroll cycles, and schedules.
How are partial weeks shown?
The result includes decimal weeks and also full weeks plus remaining days for clearer interpretation.
Does this include leap years?
Yes. JavaScript date calculations include leap years automatically, including February 29 when applicable.
Can I calculate business-only duration?
Yes. The calculator outputs weekdays separately so you can estimate business week length directly.
What is the additional feature in this redesign?
You now get a built-in ISO week number finder and a date offset calculator to add or subtract weeks from any base date.