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Date & time

Business Date Calculator

Add or subtract working days while excluding your chosen weekend and a custom holiday list.

Date conventions explained belowClear start and end values
Date workspace
Date workspace

Check which endpoints and calendar conventions are included.

See the method

Choose your dates and times

Runs on your device

Your time calculation

Your result

Let’s calculate.

Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter starting date, working days to add (negative to subtract), weekend, holiday dates — one yyyy-mm-dd per line, or none.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Move forward or backward from the starting date, counting only dates outside the weekend and holiday set. The starting date is excluded when moving; zero returns the same date.

A WORKED EXAMPLE

Using starting date = 2026-09-21, working days to add (negative to subtract) = 10, weekend = sat-sun, holiday dates — one yyyy-mm-dd per line, or none = none, the result is 2026-10-05. Change these example inputs to match your task; use the method above to check each step.

Understanding your result

No. Adding one working day starts counting on the following date. Subtracting one starts on the previous date. Zero returns the starting date even if it is a holiday.

What to keep in mind

Uses calendar dates, not elapsed hours. Holiday calendars are not fetched automatically.

Common questions

Does the starting date count?

No. Adding one working day starts counting on the following date. Subtracting one starts on the previous date. Zero returns the starting date even if it is a holiday.

Can I use a Friday–Saturday weekend?

Yes. Choose it in the weekend selector and add any local holiday dates to the list.

Methodology maintained by ClarityKit. How these tools are built and checked.