Date Calculator
Days between dates, add or subtract days, and count working days.
Difference between two dates
Add or subtract from a date
Working days between two dates
Saturdays and Sundays are skipped automatically. Taiwan public holidays and make-up workdays (補班) are not built in: paste the dates for your year from the official government calendar.
Runs entirely in your browser. Nothing you enter is uploaded.
How months and years are counted
Days are counted exactly on calendar dates, with no time zone or daylight-saving drift. Months are counted the way a lease or subscription counts them: from 15 January, one month later is 15 February. When the same day of the month does not exist, the period ends on the last day of that month, so 31 January plus one month is 28 (or 29) February; Article 121 of the Taiwan Civil Code uses the same rule. Any days left over are then counted from that anchor. By default the end date is excluded, so Monday to Friday of one week is 4 days; tick "Include the end date" to count both ends and get 5.
Working-day caveats
- Only Saturdays and Sundays are skipped automatically. Taiwan has around 115 days off a year once national holidays and long weekends are included, and some holidays are moved or followed by a make-up Saturday, so paste the official list for your year.
- Companies that work on Saturdays or run shifts follow their own calendar; the tool assumes a Monday-to-Friday week.
- Contracts that say "business days" (營業日) often also exclude bank holidays and can differ from "working days" (工作日), so check the wording.
ROC dates
Taiwanese forms and documents often show the ROC (民國) year. Add 1911 to convert it: 115/01/01 is 2026-01-01. The add-or-subtract result shows the ROC date for convenience, but enter every date here in the Western YYYY-MM-DD form.
Privacy
All dates are calculated on your device. Nothing you type, including the holiday list, is sent anywhere or stored.