DATE CALCULATOR
Date calculator, days apart in a click.
Find how many days between two dates, or add/subtract days from a date to get the target date and weekday.
Days between
—
Date offset
2026-11-19 (Thu)
Everything runs locally in your browser
Solution animation · calendar highlight
Showing 2 month(s)
What does this tool do?
It answers two questions fast: how many days between two dates (countdowns, anniversaries), and what date/weekday you get when adding or subtracting days (deadlines, payments).
FAQ
How are days counted?
By calendar days: end minus start, handling month boundaries and leap years.
Is my data uploaded?
No. Calculation happens entirely in your browser.
示例与注意事项Example & notes
一个例子A worked example
算合同到期日：起点 2026-01-31、加 3 个月，得到 2026-04-30（目标月没有 31 日时自动退到月末）。Contract end date: start 2026-01-31 plus 3 months gives 2026-04-30 — when the target month is shorter, it snaps to month end.
注意事项Things to watch
- 按自然月相加时，若目标月没有该日会退到该月最后一天，这与「加 90 天」结果不同。Adding months is calendar-based; a shorter target month snaps to its last day, which differs from adding a fixed number of days.
- 工作日计算只排除周六周日，不含法定节假日与调休。Business-day counting excludes weekends only — public holidays and make-up workdays are not included.
- 相差天数按本地零点计算，不含时分秒。Day differences are computed at local midnight and ignore hours and minutes.
相关问答More Q&A
「加 30 天」和「加 1 个月」一样吗？Is "add 30 days" the same as "add 1 month"?
不一样。前者是固定天数（1 月 31 日 + 30 天 = 3 月 1 日），后者按自然月对齐（1 月 31 日 + 1 月 = 2 月 28/29 日）。No. The first adds a fixed span; the second aligns to the calendar month, so 31 January + 1 month lands on 28/29 February.
能一次算多组日期吗？Can I calculate several ranges at once?
一次处理一组，结果可一键复制，便于接着算下一组或贴进表格。One range per pass, with a copy button so you can chain the result into the next calculation or a spreadsheet.