Date Calculator.
Add or subtract days/months/years from a date, or get the exact difference between two dates.
The date calculator for answering "what day is 90 days from now?" or "how many days between March 15 and September 7?". Handles leap years, time zones and varying month lengths without you having to think about it.
- Add or subtract days, weeks, months, years
- Exact difference between two dates (years, months, days)
- Difference in hours, minutes, or seconds
- Business days (excluding weekends)
- Handles leap years correctly
- Locale-aware formatting (DD/MM/YYYY in es, MM/DD/YYYY in en)
- 0190-day contract expiration
- 02Countdown to a specific date
- 03Gestational age for pregnancies
- 04Business days for delivery estimates
- 05Anniversaries and countdowns
fechas.util.ar
We're finishing this one. Landing will live at fechas.util.ar.
How does it handle leap years?
Using the browser's native Date object, which correctly counts leap years (every 4 years, except those divisible by 100 but not 400).
What about time zones?
Dates are processed in your local time zone. If you're in Argentina (UTC−3), differences with a UTC date reflect that.
Do business days include holidays?
We only exclude Saturdays and Sundays. Holidays vary by country and year, so they're not hardcoded. Subtract them manually if needed.
Does it support pre-1900 dates?
Yes — JS Date supports from −271821-04-20 to +275760-09-13. Plenty for genealogy or history.