Maintenance
State calendar mistakes that quietly move a real deadline without notice
Nine state calendars mistakes that quietly produce a wrong deadline, from treating the national list as complete to trusting a tool's built-in data.
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Maintenance
Maintenance
The set formula for combining closure layers into a single workday count
Set rules for layering closure calendars into a workday count: rest days first, then the union of every applicable list, with a hypothetical worked March example.
Maintenance
Country calendars holidays: a review routine for each new national closure list
A step-by-step routine for reviewing a new national closure list against the old one, so country calendars holidays changes never move a count unseen.
Maintenance
A working brief on add business days formula as of 2027
What the WORKDAY formula really does at the edges: rest-day starts, zero and negative counts, silently ignored text closures, and a hand method that matches.
Maintenance
Days between dates API: signal versus noise
Designing a days between dates API: plain dates against moments, the request and response fields worth echoing, and vectors that catch a merged type.
Maintenance
Days between dates: the method a calculator runs and the divide by seven check
The method a days between dates calculator runs, written for paper: day of year subtraction, leap years, a divide by seven check, and when to trust a tool.
Maintenance
Notes on working days per month in Excel: NETWORKDAYS, EOMONTH and month edges
How to get working days per month in Excel with EOMONTH and NETWORKDAYS, what both-end counting does at month edges, and where weekend and holiday arguments break.
Maintenance
Why a year's working day total starts with 260, 261 or 262 weekdays
Explains why a year's working day total starts with 260, 261 or 262 weekdays, how leftover days decide the count, and why closures and payroll divisors sit on top.