Calendars and Ontario statutory holidays in Microsoft Project

A schedule is only as honest as its calendar. Microsoft Project's Standard calendar works Monday to Friday, eight hours a day, every week of the year, and it has no idea that Ontario stops for Family Day, Good Friday or Canada Day. This lesson builds a proper calendar for the Northgate owner's master schedule, sorts statutory days from common days off, and records the holiday decisions the law leaves to the owner.

Learning outcomes

• Explain the four kinds of calendar in Microsoft Project desktop (base, project, resource and task) and which one wins when they disagree.
• List Ontario's nine public holidays under the Employment Standards Act, 2000 and identify common days off, such as the Civic Holiday, that are not on the list.
• Create a base calendar, enter holiday exceptions and apply the calendar to a project.
• Record the owner's holiday decisions so the owner's and contractor's schedules can be compared.

The lesson

Four kinds of calendar

Microsoft Project desktop schedules work only in working time, which comes from four kinds of calendar (Figure 1).

• Base calendars are templates stored in the file. Project ships with Standard (Monday to Friday, 8:00 a.m. to 5:00 p.m. with an hour for lunch), 24 Hours and Night Shift.
• The project calendar is the base calendar you pick in Project > Project Information. Every task follows it unless something overrides it.
• Resource calendars belong to people and equipment. Each one starts from a base calendar (the project calendar by default) and adds that resource's own leave or shifts.
• Task calendars override the project calendar for a single task, for example a seven-day concrete cure. When a task has both a task calendar and assigned resources, Project schedules only in the time both calendars share, unless you tick Scheduling ignores resource calendars in the Task Information dialog box.

For an owner's master schedule, keep it simple: one good project calendar, and task calendars only where the work truly runs on a different pattern. Every extra calendar needs checking.

What the Standard calendar gets wrong

Standard has the right shape for Northgate (five days, eight hours) but no holidays at all. Each missing holiday is a day Project treats as productive when the site is closed. Over a 12-month build that is about two weeks of hidden optimism. Lesson 3 left the Northgate file on Standard; now we replace it.

Ontario's public holidays

Ontario's Employment Standards Act, 2000 (ESA) lists nine public holidays: New Year's Day, Family Day, Good Friday, Victoria Day, Canada Day, Labour Day, Thanksgiving Day, Christmas Day and Boxing Day. Ontario's guide to the ESA notes that some employers also give Easter Monday, the first Monday in August (the Civic Holiday) or Remembrance Day, but the ESA does not require it. They are not public holidays.

Two more points matter for schedulers:

• Weekend holidays. When a public holiday falls on a non-working day, the ESA gives the employee a substitute day off (or holiday pay, if the employee agrees in writing). The Act does not fix the substitute's date, so the day a site actually closes is set by employers and agreements. Christmas and Boxing Day 2027 fall on a weekend, and so does New Year's Day 2028.
• Construction has special rules. For example, Ontario's guide says public holiday pay does not apply to construction employees who receive vacation or holiday pay of at least 7.7% of hourly wages (9.7% after five years). Many trades also work under collective agreements with their own holiday lists. The days a crew actually works are the contractor's to declare.

For scheduling, the point is not holiday pay: the calendar is a planning assumption, and the owner should state it rather than inherit it. Table 1 lists the Northgate dates.

Figure 2 turns the table into a rule you can apply to any year.

Building the calendar, step by step

1. Create the base calendar. Go to Project > Properties > Change Working Time and choose Create New Calendar. Name it Northgate 5x8 ON and make it a copy of Standard.
2. Check the work week. On the Work Weeks tab, select the default row and choose Details. Confirm Monday to Friday are working, 8:00 to 12:00 and 13:00 to 17:00, and Saturday and Sunday are non-working.
3. Enter the exceptions. On the Exceptions tab, type a name such as Family Day 2027 and set Start and Finish. New exceptions are non-working by default. Enter every non-working row from Table 1; one row can span two days.
4. Apply it. Go to Project > Project Information and set Calendar to Northgate 5x8 ON.
5. Match the duration settings. In File > Options > Schedule, under calendar options, hours per day, hours per week and days per month (8, 40 and 20 by default) tell Project what "1 day" or "1 month" means when you type a duration. They do not change the calendar. For Northgate the defaults match; a 10-hour-day calendar would need them changed too.
6. Keep it for next time. Calendars live inside the file. Save it as a template, or copy the calendar to the global template with the Organizer (File > Info > Organizer, Calendars tab).

In Figure 3: pick (1) or create (2) the calendar, enter exceptions (3), use Details (4) for recurrence, and check the Work Weeks tab (5).

Recurring exceptions: use with care

The Details button lets an exception repeat, for example yearly. That suits Family Day (the third Monday of February), but not Good Friday, which follows Easter, or Victoria Day, the Monday before May 25, which can be the third or fourth Monday of May. A yearly July 1 rule also ignores weekend substitutes: Canada Day 2028 is a Saturday. One-off exceptions per year are clearer and easier to audit. Enter holidays at least a year past the planned finish so a slip does not run into an empty calendar.

Screenshot to come

Northgate worked example

Northgate Distribution Centre (fictional) is a 12,000 m² tilt-up warehouse in Vaughan, Ontario, for Northgate Logistics Inc. (fictional). The owner's master schedule, NDC_OwnerMaster_2027-01-11.mpp, runs from contract execution (M0, Mon 2027-01-11) to final completion (M11, Fri 2028-03-31), Monday to Friday, eight hours a day, with Ontario statutory holidays non-working (see the Northgate fact sheet). The fact sheet does not say what to do with weekend holidays or non-statutory days, so the Owner's PM records three decisions in the schedule's basis notes:

Northgate decisions (owner's calendar). (1) The Civic Holiday (Mon 2027-08-02), Easter Monday and Remembrance Day are working days, because they are not ESA public holidays. (2) When a public holiday falls on a weekend, the next weekday is non-working: Mon 2027-12-27, Tue 2027-12-28 and Mon 2028-01-03. (3) Any winter shutdown or other non-working days are the contractor's to declare in its P6 calendar; the owner's file does not guess them.

Decision 1 is a planning choice, not a legal one. The owner is not telling Halvorsen Builders Ltd. (fictional) to work on August 2; its forecast simply does not assume the site is closed. If Halvorsen's calendar shows August 2 as non-working, the schedules differ by one day from then on, and the reviewer knows why.

With the calendar applied, Figure 4 shows the working days per month across the owner's file.

View the data

Month	Weekdays	Holidays removed	Working days
Jan 2027	21	1	20
Feb 2027	20	1	19
Mar 2027	23	1	22
Apr 2027	22	0	22
May 2027	21	1	20
Jun 2027	22	0	22
Jul 2027	22	1	21
Aug 2027	22	0	22
Sep 2027	22	1	21
Oct 2027	21	1	20
Nov 2027	22	0	22
Dec 2027	23	2	21
Jan 2028	21	1	20
Feb 2028	21	1	20
Mar 2028	23	0	23

The totals are what matter. From M0 (Mon 2027-01-11) to M9 Ready-for-Takeover (Fri 2028-01-14), there are 265 weekdays but only 256 working days in the Northgate calendar: nine holidays fall in that window. On the Standard calendar, a chain of work that really needs 256 working days would show a finish nine working days (almost two weeks) too early. Three of them (December 27 and 28, and January 3) fall in the last three weeks before M9, in the middle of commissioning, which starts at M8 (Mon 2027-11-01).

Screenshot to come

Screenshot to come

Owner's move

• Ask for the contractor's calendars in writing. With every baseline and update, ask for each P6 calendar, its work week, its holidays and the activities that use it.
• Compare, do not copy. Lay the contractor's holiday list beside Table 1. Explain every difference (Civic Holiday, shutdown, Saturday work); do not quietly reconcile it.
• Write your decisions down. Put the owner's calendar rules in the schedule basis memo, as Northgate did, so anyone can rebuild your working days from it.
• Check the calendar column. Add the calendar column in both schedules and look for odd ones out. One task on a 24-hour calendar can make a path look shorter than it is.

Common mistakes

1. Staying on Standard. No holidays, optimistic finish: nine working days on Northgate.
2. Treating the Civic Holiday as statutory. It is not an ESA public holiday. Whether it is working time is a decision; make it explicitly.
3. Forgetting weekend substitutes. Christmas 2027 falls on a Saturday; without observed days, it removes no working time.
4. Using yearly recurrence for moving holidays. Good Friday and Victoria Day do not follow a fixed pattern Project can express.
5. Changing the calendar but not the conversion settings. A 10-hour calendar with "8 hours per day" in Options distorts typed durations.

Quick quiz

1. Which of these is an Ontario public holiday under the ESA?

   1. Civic Holiday
   2. Easter Monday
   3. Family Day
   4. Remembrance Day

2. Where do you set the calendar that every task follows by default?

   1. Task Information > Advanced
   2. Project > Project Information > Calendar
   3. File > Options > Display
   4. Resource Sheet > Base Calendar

3. Christmas Day 2027 falls on a Saturday. What does the Northgate owner's calendar do?

   1. Nothing; the day is already non-working
   2. Makes Fri 2027-12-24 non-working
   3. Makes Mon 2027-12-27 non-working
   4. Makes the whole week non-working

4. Why is a yearly recurring exception a poor choice for Good Friday?

   1. Project cannot make exceptions recur
   2. Its date follows Easter and changes every year
   3. It is not a public holiday
   4. Recurring exceptions are working time by default

5. On the Standard calendar, roughly how early would the Northgate M9 date show if the real work needs 256 Northgate working days from M0?

   1. Not at all
   2. About two days
   3. About two weeks
   4. About two months

Show answers and explanations

1. C. Family Day is one of the nine. The other three are common days off, not ESA public holidays.
2. B. The project calendar is set in Project Information; a task calendar overrides it for one task.
3. C. The ESA does not fix the substitute's date. Northgate chose the next weekday, so Christmas moves to Monday and Boxing Day to Tuesday.
4. B. Good Friday follows Easter, so no fixed yearly pattern can match it. Enter it once per year.
5. C. Nine holidays fall between M0 and M9, so the Standard calendar finishes nine working days (almost two weeks) early.

Key terms

Base calendar

A calendar template stored in the file (Standard, 24 Hours, Night Shift or your own) that can be used as a project, resource or task calendar.

Project calendar

The base calendar chosen in Project Information that sets working time for all tasks unless overridden.

Task calendar

A base calendar assigned to one task to override the project calendar.

Exception

A dated change to a calendar's normal work week, such as a holiday, entered on the Exceptions tab of Change Working Time.

Public holiday (Ontario)

One of the nine days listed in the Employment Standards Act, 2000. Called a statutory holiday in everyday use.

Substitute day

A day off given in place of a public holiday that falls on a non-working day.

Schedule basis memo

A short document recording the assumptions behind a schedule, including its calendar rules.

References

1. Ontario.ca, Your guide to the Employment Standards Act: Public holidays.
2. Ontario.ca, Industries and jobs with exemptions or special rules: Manufacturing, construction and mining.
3. Employment Standards Act, 2000, S.O. 2000, c. 41, s. 1(1) (definition of public holiday), Ontario e-Laws.
4. Microsoft Support, Add a holiday to the project calendar.
5. Microsoft Support, Set the general working days and times for a project.
6. Microsoft Support, Create a new base calendar.
7. Microsoft Learn, Application.OptionsCalendar method (Project) (hours per day, hours per week and days per month settings).
8. Canada Holidays, Ontario holidays 2027 (cross-check of dates).
9. BRC Academy, Lesson 3: Create a project and set the start date.

Verified on November 4, 2026.

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