Costs
Excel date serials and the 1900 and 1904 epochs: spreadsheet and API date handling
Excel date serials, the 1900 and 1904 epochs, text date traps, and spreadsheet and API tools that move dates without shifting or corrupting them.
Desk
Planning Desk
Timelines, dependencies and the order that keeps business days and workday calculators from stalling.
Industry
SLA deadline mistakes: the blind spots that make two teams read the clock differently
Nine SLA deadline mistakes that leave two parties calculating different things: mixed units, undefined pauses, the wrong timestamp, and a stale calendar.
Rules
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.
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.
Guides
Multiple working calendars in one Excel sheet: WORKDAY.INTL weekend strings
How to hold several working calendars in one Excel sheet: WORKDAY.INTL weekend strings, a calendars and closures table lookup, and what breaks.
Reviews
9 working-hours mistakes that produce a wrong deadline without warning
Nine working hours mistakes that cause wrong deadlines: dividing elapsed time by eight, the missing window zone, and the day that is not 24 hours long.
Guides
Canada Post delivery standards business days: how they count
Canada Post delivery standards business days start at the acceptance scan. It covers weekends, statutory holidays, local cut-offs and cross-border handover.
Guides
4 rules for counting Nova Scotia and Newfoundland business days in Halifax and St. John's
Nova Scotia and Newfoundland business day counts need both provincial holiday lists, plus port and offshore calendars that close on days the province is open.
Guides
Ottawa's federal public service calendar for contractors counting business days
Federal public service holidays in Ottawa do not match Ontario's statutory list, and that gap moves contract and SLA deadlines by a day or more.
Costs
Working hours holidays: a dated, sourced directory
Working hours holidays in 2027: the closure dates that move deadlines, who publishes each one, and how to check the list your filing depends on.
Rules
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.
Rules
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.
Rules
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.
Rules
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.
Guides
How to Count USPS Business Days for Delivery Estimates
A USPS business day delivery calculator counts Monday to Saturday, not federal days. Here is the one rate worth tracking and the point where you act on it.
Rules
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.
Features
Monday to Friday totals for any year: why the count is only 260, 261 or 262
How to count Monday to Friday weekdays in a year: 52 weeks give 260, leftover days add one or two, and the total is 260, 261 or 262. The table covers all start days.
Guides
Days between dates holidays: past and future windows
How a closure changes a days between dates count, and why a window that has closed and one that has not must be counted against different lists.
Costs
Subtract business days API: direction, request fields, and response shape
How to design a subtract business days API: putting direction in its own field, the request fields it must carry, and what a response should echo back.
Industry
Subtract business days formula: WORKDAY and worked cases
How WORKDAY with a negative count subtracts business days: the three arguments, weekend strings for other weeks, and worked deadline cases.
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.