Date & Calendar Math Calculator • දින සහ කැලැන්ඩර් කැල්කියුලේටරය
Compute exact days between two calendar dates, leap years, statutory notice intervals, or add and subtract days, weeks, and months from any date.
1. Days Between Two Dates (දින දෙකක් අතර කාලය)
Calculate elapsed days between two calendar dates
2. Add or Subtract Days from Date (දින එකතු කිරීම හෝ අඩු කිරීම)
Find the future or past target date
Standard Calendar & Statutory Notice Intervals (ශ්රී ලංකාවේ දින සීමා)
Common statutory notice periods, warranty deadlines, and standard calendar durations used across employment and property agreements in Sri Lanka.
| Interval Name | Calendar Days | Working Days (Approx.) | Standard Sri Lankan Context |
|---|---|---|---|
| 1 Week (සතියක්) | 7 Days | 5 Days | Standard payroll sprint / cooling-off |
| Fortnight (සති දෙකක්) | 14 Days | 10 Days | Legal notice / urgent court summons |
| 1 Month Notice (මාසයක දැන්වීම්) | 30 Days | 21–22 Days | Tenancy lease & standard resignation notice |
| 1 Quarter / Probation (මාස 3) | 90 Days | 64–66 Days | Initial employee probation period |
| 1 Calendar Year (වසරක්) | 365 / 366 Days | ~250 Days | Tax assessment year (1 April to 31 March) |
Frequently Asked Questions • නිතර අසන ප්රශ්න
How is the number of days between two calendar dates calculated?
The tool computes the absolute elapsed duration in milliseconds between the start date at 00:00:00 and the end date at 00:00:00, then converts milliseconds into total days, weeks, and remaining days while accounting for leap years with 366 days.
How do leap years affect calendar date calculations?
Leap years occur every 4 years (e.g. 2024, 2028), adding February 29th to make a 366-day year. Our date calculator natively factors in leap year logic so date intervals spanning February are 100% exact.
Can I add or subtract a specific number of days from any date?
Yes, you can input a starting date and add or subtract any number of days, weeks, or months to determine the exact future deadline, contract expiry, or historical milestone.
How does this tool help with legal agreements and notice periods in Sri Lanka?
Sri Lankan tenancy agreements, employment termination notices (such as 30-day or 3-month statutory notice), and court filing periods require exact calendar day counting. This tool ensures that notice dates are computed without human error.
Calendar Duration & Date Arithmetic
Calculate project timelines, contract periods, leave allocations, or deadlines with exact Gregorian calendar arithmetic including leap day tracking.
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