在线日期计算工具，计算两个日期之间的天数差，或对指定日期进行加减操作（天、周、月、年）。
Calculate date differences or add/subtract days, weeks, months, years
Runs locally · Nothing uploaded
Our online date calculator provides convenient date difference and date arithmetic functions. Quickly calculate the number of days between two dates, or add/subtract days, weeks, months, and years from a given date. Supports business day mode that automatically excludes weekends. Accurately handles leap years, ideal for project scheduling, countdowns, tenure calculations, and more.
The result represents the number of natural days between two dates. For example, January 1 to January 3 shows 2 days. If you need to include both the start and end dates, add 1 to the result.
When adding or subtracting months results in an invalid date (e.g., January 31 + 1 month), the result automatically adjusts to the last day of that month. For example, January 31 + 1 month gives February 28 (common year) or February 29 (leap year).
Calculations are based on the local time zone. For cross-timezone date calculations, it is recommended to convert all dates to the same time zone first to ensure accurate results.