Date Calculator
Compute the days/weeks/months/years between two dates, and add/subtract days, months, years from a date.
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Add / subtract from a date
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How to use
- Pick "Start date" and "End date" to see the exact day gap plus week/month/year estimates.
- Choose a "Base date" and add/subtract days/months/years for the result.
- Months/years roll over years and handle month-end overflow by calendar rules.
- Tip: days are exact; months/years use avg 30.44/365.25 days for reference only.
FAQ
How are months and years derived?
Days are exact; weeks = days/7; months use avg 30.44 days and years 365.25 for quick reference, not calendar-exact months.
Does adding months cross years?
Yes. The tool uses Date setMonth/setFullYear, following calendar rules to roll over years and handle month-end overflow.