In what order are years, months, and days applied?
Years and months are applied first to establish the destination month, followed by day clamping and day-offset arithmetic.
Can I leave fields like years or months at zero?
Yes. Any field set to 0 is treated as zero offset, allowing flexible combinations.
How does the calculator handle year rollovers?
Adding 14 months to January 2026 advances 1 full year and 2 months to March 2027.
What happens when subtracting past January 1?
The calculator decrements the year and wraps months smoothly into the prior calendar year.
Can I calculate the difference between two dates instead of adding?
Use our Date Difference Calculator to decompose the span between two dates into years, months, and days.
How does the Date Calculator work?
It computes the difference in milliseconds between two dates and converts that to days, weeks, and months.
Does it include weekends?
The total days include weekends. The working days count excludes Saturday and Sunday.
Can I add months to a date?
Yes — use the Add/Subtract mode and enter the number of years, months, and days to add.
Is it accurate for leap years?
Yes, JavaScript's Date object handles leap years automatically.
What date format should I use?
Select dates using the date picker — no manual typing needed.
Can I calculate negative differences?
Yes — if the end date is before the start date, the result will show accordingly.
Is it free?
Yes, completely free with no registration required.
Does it save my data?
No data is stored. All calculations happen in your browser.