About the Date Difference Calculator
A precise date calculator built for project planners, HR teams, and anyone who needs the exact gap between two dates.
What it is
The Date Difference Calculator tells you exactly how much time separates any two dates — in days, weeks, months, and years — the instant you pick them. There's no button to click, no page to refresh. Set a start date and an end date and every figure updates immediately.
Everything runs in your browser. Your dates are never sent to a server, stored, or logged anywhere. Close the tab and they're gone.
What it calculates
Days
The exact calendar day count between the two dates, accounting for leap years and varying month lengths.
Weeks
Whole weeks in the duration — helpful for scheduling in weekly sprints, billing cycles, or recurring events.
Months
Full calendar months spanned — useful for contract notice periods, subscription lengths, and loan terms.
Years
Complete years in the date range — great for anniversaries, tenures, and multi-year project windows.
Working Days
Monday–Friday only, with weekends stripped out. Toggle it on to count business days for deadlines and payroll periods.
Inclusive Count
Days + 1 to include both the start and end date — useful when a policy or contract counts both endpoints.
Standout features
Working Days Toggle
Flip one checkbox and the calculator instantly switches from calendar days to business days (Mon–Fri). Perfect for SLA windows, sprint lengths, and payroll periods where weekends don't count.
Next Occurrence Finder
Enter any date — a birthday, an anniversary, a renewal date — and the tool tells you the next time that day comes around, including Feb 29 for leap-year dates.
Swap Button
Entered the dates in the wrong order? One click swaps start and end without retyping, and the result updates immediately. The calculator always works with the earlier date as the starting point.
Leap Year Aware
February 29 and ranges that cross a leap year are handled correctly. Whether you're checking a 4-year anniversary or a range spanning multiple Feb 29s, the count is always exact.
Who it's for
Project managers
Count business days between milestones, check sprint lengths, or verify SLA windows without a spreadsheet.
HR & payroll teams
Calculate working days in a pay period, check notice periods, or verify employment durations in seconds.
Legal & contracts
Verify contractual durations, notice periods, and limitation windows with day-accurate calendar counts.
Travellers & planners
Check trip lengths, days until departure, or time remaining on a visa without mental arithmetic.
Completely free
No account, no rate limit, no premium tier. Calculate a two-day gap or a fifty-year span — both are instant. If you find it useful, sharing it with a colleague who needs a quick date count is all we ask.