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An add or subtract dates calculator computes a new date by adding or subtracting a specified number of days, weeks, or months from a starting date. Used for deadlines, scheduling, and date planning.
Формула
result_date = start_date ± days (accounting for month/year boundaries)
- start
- Start date (date) — Base date (YYYY-MM-DD)
- days
- Days to add/subtract (days) — Positive = future, negative = past
- result
- Result date (date) — The calculated date
Водич чекор-по-чекор
- 1For days: add/subtract directly from the date
- 2For weeks: multiply by 7 then add/subtract days
- 3For months: adjust the month field and handle month-end overflow
- 4JavaScript Date handles leap years automatically
Worked Examples
Влез
Jan 15 + 90 days
Резултат
April 15 (or 16 in leap year)
Влез
Mar 31 + 1 month
Резултат
April 30 (month-end handling)
Влез
Today − 30 days
Резултат
Date 30 days ago
Frequently Asked Questions
How does the calculator handle month boundaries?
It automatically adjusts for varying month lengths and leap years. Adding 30 days to Jan 1 correctly lands on Jan 31.
Can I subtract dates to go backward in time?
Yes, use a negative number. Subtracting 10 days from Mar 15 = Mar 5. The calculator respects month/year boundaries.
What about leap seconds or daylight saving?
Calendar calculations ignore leap seconds and DST. They operate on calendar dates, not absolute time.
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