Rules
Fifteen worked examples of business day counting across stacked closure layers
Fifteen worked examples over one invented three-layer closure arrangement in March 2027, counting and stepping business days with the arithmetic shown.
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Rules
Rules
Spreadsheet Date and Workday Counting Mistakes
Spreadsheet date and workday-count mistakes: text dates, locale-dependent imports, midnight shifts, serial values, endpoint rules, and closure ranges.
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Spreadsheet and API tools formula testing for parity
Spreadsheet and API tools formula parity: Excel NETWORKDAYS against Nager.Date, four pinned conventions, sixteen boundary cases, and the 1900/1904 epoch trap.
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Federal Holiday Business Day Counting: Project Dates
Federal holiday business day counting with a real 2025 Memorial Day example, the one-day date shift, and a formula for rebuilding the schedule.
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SLA deadline clocks: what your contract must say about calendars and closures
SLA deadline clocks depend on contract terms: which calendar is named and versioned, rest days, substitution, mid-term changes, and what to store per clock.
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Alberta Energy Regulator filings, counting business days in Calgary and Edmonton
AER filing business days Alberta: how the regulator counts submission deadlines against Alberta statutory holidays, with worked examples for Calgary and Edmonton.
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CRA business day deadlines: GST/HST and corporate dates
CRA business day deadlines for GST/HST and corporate returns: find the statutory date, check CRA holidays, and apply the weekend or holiday shift.
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Quebec Construction Holiday Business Days: Schedule Impact
Quebec construction holiday business days can distort project schedules because standard holiday lists omit the closure. Learn the date rule and adjust counts.
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A Guide to CRA Business Day Deadlines and Counts
CRA business day deadlines and counts, explained stage by stage: filing dates, payments and objections, plus the shift rule that moves a due date.
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A Guide to Federal Holidays in Business Day Counts
A federal holiday business day calendar drifts when the OPM and Federal Reserve lists are mixed up. Two closures separate them, and both can move a deadline.
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Federal vs State Court Filing Deadlines: Counting Business Days
Federal vs state court filing deadlines: how FRCP 6 and state rules count business days, holidays and mail service differently, and where each count goes wrong.
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IRS response deadlines: calendar days, not business days, and when dates move
Most IRS response deadlines count calendar days, not business days. This explains start dates, weekend and holiday moves, postmark proof, and missed dates.
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Working days per year API: the version that survives contact with reality
A working days per year API is a caching problem: pin the calendar version, define which year you mean, and make the response carry its own provenance.
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Add business days: three start conventions and fifteen worked cases excluding the start
Fifteen worked add business days cases excluding the start, plus how the three start-day conventions and a closure really move an actual deadline.
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Country calendars: three origins of a closed day
Country calendars: the three kinds of closed day, how a national list is published, and the fields to capture before you rely on one for a deadline.
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Days between dates formula: build the day number and test it
A days between dates formula built on a March-first day number, tested on leap days and century years, then reconciled with a spreadsheet's NETWORKDAYS.
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Subtract Business Days Holidays 2027: U.S. Example
Subtract business days holidays 2027 with a U.S. example: how OPM’s observed July 5 closure shifts a backward count and which calendar should govern.