# Business-day calculator

Canonical interactive tool: https://taskpencil.com/tools/business-day-calculator/

Count working days or add working days while excluding selected weekdays and entered holidays.

## Instructions

1. Enter your values in the labeled fields.

2. Results update automatically as inputs change. Review the result and assumptions.

3. Copy or print your result.

## Formula and example

Count dates that fall on an allowed weekday and are absent from your holiday list. With Saturday/Sunday excluded and both endpoints included, Monday October 5 through Friday October 9, 2026 gives 5 working days. Adding 5 working days to October 5 gives October 12 because the start is day zero.

## Limits

Dates from 1900 through 2200. Enter your own holidays, including observed dates when relevant; none are automatically supplied. Duplicate holidays and holidays on excluded weekdays are excluded once. Counting requires end on or after start; adding accepts negative whole days. At least one weekday must remain working. Date-only arithmetic avoids time-zone and daylight-saving shifts. All processing is local; inputs are not stored or transmitted.