Date and Planning Tools
Choose the right calculator for week numbers, date ranges, business days, working days, deadlines, project timelines, payroll periods and timesheet weeks.
Core week calculator
The main Weeks Calculator is one page with five calculation modes: date to ISO week number, week number to date, weeks between dates, add or subtract weeks, and weeks from today. Use it when you want one flexible tool without opening a separate page for each mode.
Date & Work Calculators
Focused calculator pages for days, business days, working days and ISO week numbers.
Days Between Dates Calculator
Count exact days, full weeks, and remaining days between any two dates.
Open tool →Business Days Calculator
Count weekdays between two dates and skip weekends for business planning.
Open tool →Working Days Calculator
Count working days with a custom workweek instead of a fixed Monday-to-Friday schedule.
Open tool →Week Number Calculator
Convert any date into an ISO week number, week-year, and week range.
Open tool →Planning Calculators
Planning tools for deadlines, project timelines, work anniversaries, payroll periods and timesheet weeks.
Deadline Calculator
Add calendar days, weeks, or business days to a start date to find a deadline.
Open tool →Project Timeline Calculator
Estimate a project end date from a start date, week-based duration, and optional buffer.
Open tool →Work Anniversary Calculator
Find years of service, total weeks employed and the next work anniversary date.
Open tool →Payroll Period Calculator
Estimate weekly and biweekly payroll period ranges from a payroll start date.
Open tool →Timesheet Week Calculator
Find the ISO week number and Monday-to-Sunday range for any timesheet date.
Open tool →