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Working Days Calculator

Count or add working days with a custom weekly schedule, selected OPM-observed U.S. federal holidays, and configurable work hours per day.

Use this result well

Inputs that matter
Range or add mode, valid date(s), whole workday count, custom seven-day work schedule, selected U.S. federal holidays, and work hours per counted day
Output to expect
Working-day total or target date, calendar dates traversed, mutually exclusive holiday/schedule exclusions, and work-hour total
How it works
UTC-stable date-only iteration; range mode includes both endpoints, while add mode treats the start as day zero and begins on the following date
  • Federal dates use OPM names and standard Monday–Friday weekend observation; alternative schedules and local/employer closures can differ.
  • Each date is classified once, so a selected holiday on a non-working schedule day is not double-counted.

Choose your path

Built around the job you need to finish

Count an inclusive custom work schedule or add whole working days after a start date using mutually exclusive schedule and selected-holiday exclusions.

Delivery-window planner

Count both endpoints under a real weekly schedule.

Use range mode, select workweek/holidays, set hours per day, and inspect the classification totals.

Every date reconciles once as working, selected holiday, or non-working schedule date.

Service-level operator

Find the date N workdays after receipt without counting receipt as day one.

Use add mode from the receipt date and inspect dates traversed and exclusions.

Starting Sunday 2026-08-23 plus 10 standard workdays returns Friday 2026-09-04 and labels the start as day zero.

Nonstandard-schedule employee

Model a sparse or weekend-inclusive workweek without an iteration failure.

Toggle the seven-day schedule and selected federal dates, then review result and hours.

A valid sparse schedule completes, while zero selected workdays is explicitly rejected.

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Projects using Working Days Calculator

This tool is part of these guided projects. Each project provides step-by-step instructions with checklists and all the tools you need in one place.

Work Schedule Decision Record

Coordinate one work schedule from authority, compensable-time and accommodation boundaries through dated calculations, time-zone checks, coverage evidence, publication and review.

6 steps8 toolsStart project

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Reference & details

How it works

Range and add conventions

Range mode is inclusive. Add mode excludes the starting date and iterates forward from the following date.

Target = first date after start that completes N eligible workdays

Date-only iteration

Dates are parsed and advanced as UTC calendar days, so daylight-saving transitions do not change a count.

Holiday and hours scope

Selected federal holidays follow OPM names and standard Monday–Friday observation. Work hours equal counted days times the user-entered hours/day and are not a payroll determination.

Updated: July 2026

Example Scenarios

A project manager counts an inclusive delivery window using the team's actual weekly schedule and selected federal dates.

An operations user adds ten working days after receipt, with the receipt date explicitly treated as day zero.

An HR coordinator runs an initial schedule estimate, then verifies employer policy and non-federal closures before acting.

FAQ

Yes. Range mode classifies both the start and end dates. Each date becomes exactly one of: working, selected holiday, or non-working schedule date.

No. The start date is day zero. Counting begins on the next calendar date and stops when the requested number of eligible working days has been reached.

For the standard Monday–Friday schedule, a fixed holiday falling Saturday is observed Friday and one falling Sunday is observed Monday, following OPM's general rule.

No. State, local, employer, school, emergency, and alternative-work-schedule closures can differ. Select only the dates relevant to your plan and verify consequential deadlines.

No. A selected holiday is classified first; other dates that are outside your weekly schedule are classified separately. The exclusion totals remain mutually exclusive.

About Working Days Calculator

Use range mode for an inclusive schedule count or add mode to find a target date after a whole number of working days. Customize the seven-day workweek, federal exclusions, and hours per counted day.