Contracts and payment terms
Push a signing date 30 days, 6 months or 3 years forward to see the exact due date and weekday.
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Guide
Date Calculator handles three kinds of date arithmetic: date difference, date projection and a simple age calculation. Difference mode shows how many days, how many weeks and days, and how many months and days two dates are apart, and roughly counts the weekdays in between; projection mode adds or subtracts days, weeks, months or years from a base date in either direction; age mode works from today and gives the exact age, a simplified Chinese nominal age (xusui), cumulative days/months and the next birthday.
Updated 2026-09-102 min read
| Input | Output | Notes |
|---|---|---|
2026-01-01 → 2026-01-31 |
30 days |
The day count excludes the start date |
2026-01-31 plus 1 month |
2026-02-28 |
The month end follows the date library's rule and lands on the target month's last day |
(start, end] consistently with the day difference; public holidays are not deducted and shifted weekend workdays are not counted as business days.Push a signing date 30 days, 6 months or 3 years forward to see the exact due date and weekday.
See how many calendar days, and how many Monday-to-Friday days, fall between two milestones, then decide whether you need a stricter holiday-aware figure.
Because only Saturdays and Sundays are excluded here; public holidays and shifted working days are unknown to the tool. For Chinese holiday scenarios use the Business Days tool.
This page uses the simplified Gregorian year-difference formula; the standalone Age Calculator follows changes of the lunar year when the lunar-calendar module is available.
All date arithmetic runs locally in your browser; nothing is saved and no network requests are made.
Updated 2026-09-10
Days between dates (including business days), add or subtract N days/weeks/months, exact and nominal age
2026年9月27日 星期日 → 2026年10月27日 星期二