Working Day Calculator: Date Range, Delivery and Backcasting

Working Day Calculator: Date Range, Delivery and Backcasting: purpose and instructions

Calculate the number of working days between two dates, or calculate the delivery date backward by the specified number of days, or the preparation date forward. You can import the date range from the annual calendar, select the government office calendar or customize rest days, then check the day-by-day details, copy or download CSV. Government holiday and compensatory leave information is limited to 2026 and 2027, which have been verified, and does not directly represent the shift schedule of individual companies.

How to use

Fill in the date range, or confirm the entry after selecting the start and end date in the almanac; when calculating the delivery date, select backward or forward and the number of working days.
Select the government office calendar, or customize weekly rest days, holidays, and compensation leave exclusion methods.
Check business days or projected dates, perform a day-by-day reconciliation, copy the results or download the full CSV details.

Frequently asked questions

Will the date range include the start day and end day?: The interval calculation can optionally include the start day. The end day will be included in the range, but rest days and holidays are still excluded according to the selected rules. For example, according to the government office calendar, 2026/10/5 to 10/9 and including the start date, there are a total of 5 calendar days and 4 working days, and 10/9 is a compensatory holiday for government agencies.
Starting from 2026/10/5, what day will it be in 5 working days?: Using the government office calendar and extrapolating back 5 working days without starting day, the result is 2026/10/13. The day-by-day breakdown excludes the 10/9 compensatory holiday, the 10/10 National Day, and the 10/11 weekend; results may be different when using a custom work week instead.
If the delivery date is known, how can we push back the preparation date?: Select "Estimated delivery date", use the delivery date as the starting date and select "Project forward". For example, if you push back 3 working days from 2026/10/12, according to the government office calendar and excluding the starting date, the result will be 2026/10/6. Please check with the actual agreement with the daily details.
Can the date selected in the almanac be directly brought into the calculation?: Yes. After selecting the start and end date in the calendar, click to bring it into working day calculation, and then confirm the application. After applying, switch to the interval calculation including the start and end dates, and retain the current government/customized work week settings; if not applied temporarily, the original calculation draft will remain unchanged.
Can weekends and national holidays be excluded from the calculation of working days?: You can use the government office calendar, or customize weekly rest days, and then choose whether to exclude the original dates of holidays and government agencies' compensatory holidays in the government calendar. If multiple leave conditions are met on the same day, only one deduction will be made.
Can the government calendar be used to calculate delivery dates for all companies?: The government office calendar does not directly represent the work schedule of each company. Please choose the work rules that comply with the agreement. When using government holiday or compensatory leave data, only the verified data for 2026 and 2027 are currently supported and will not be updated in real time.

Related tools

Inventory reconciliation — Check the book and actual quantity according to the product number, and list the shortages, surpluses and items to be reviewed.
Booking conflict checker — Check overlapping time periods for appointments with the same resource and on the same day, and retain the original sequence numbers for manual coordination.
Time zone meeting planner — Use Taipei time to compare with Tokyo, London and Los Angeles to check the complete date and daylight saving time.
Amount and date conversion — The amount, Republic of China and AD dates in Chinese capital letters, copy them as you like.
URL QR code generator — Check the complete public URL, generate a black and white QR Code in the browser and download the PNG.
List sorting and deduplication — Organize multi-line lists, items or codes and remove blank lines and duplicate items.
Double list comparison — Check the scheduled and actual lists, listing items that are only in A, both parties, and only in B.
Text version differences — Compare the two versions of the notice or process text line by line, and list the identical, new and deleted content.
Batch file name planner — Paste the file name, arrange the prefix, serial number and file extension, and take away the complete comparison table.
Meeting agenda schedule — Fill in the start time and topic minutes, and list the start and end time of each item and the complete agenda.
Random grouper — Paste the list of participants, specify the number of groups, and arrange random groups with a balanced number of people.
Countdown to work and meetings — Set a period of time, start, pause and continue the countdown, and clearly grasp the time.
Duty roster — Arrange the rotation according to the date, week and personnel order, and check the complete arrangement and the number of times per person.
StarShare cross-device file transfer — Transfer files, text and links between mobile phones and computers without installation or login.