Calculators · Local processing
Date Calculator
Find days between dates, add or subtract calendar units, and count weekdays without timezone shifts.
Timezone-safe calendar math
Calculate dates and elapsed days
The practical guide
Perform leap-year-aware date math with date-only logic.
Three modes cover elapsed time, calendar addition or subtraction, and inclusive weekday counts.
Difference between dates
See total days, weeks plus days, and a calendar-aware years, months, and days breakdown.
Add or subtract safely
Adding a month to a month-end date clamps to the last valid day, such as January 31 to February 28 or 29.
Weekdays are not holidays
Weekend exclusion uses Monday through Friday only. No public holiday database is loaded or implied.
Privacy by architecture
Your files and tool inputs stay in your browser.
The selected files, inputs, settings, and outputs are processed in this page and are not uploaded to any server.
Questions, answered
Frequently asked questions
Does it handle leap years?
Yes. Calendar month lengths and February 29 are handled explicitly.
Can daylight saving time change the result?
No. Calculations use UTC date-only values rather than local clock durations.
Are public holidays excluded?
No. The working-day mode can exclude weekends but does not claim holiday support.