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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
Пошаговое руководство
- 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
Решённые примеры
Ввод
Jan 15 + 90 days
Результат
April 15 (or 16 in leap year)
Ввод
Mar 31 + 1 month
Результат
April 30 (month-end handling)
Ввод
Today − 30 days
Результат
Date 30 days ago
Часто задаваемые вопросы
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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