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Project Calendar

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Overview

The project calendar defines what counts as working time: which days of the week are work days, how many hours are in one of them, and which dates are holidays. Two things depend on it:
  • The schedule Monte Carlo simulation steps durations forward through working days, so the calendar decides whether a simulated 30-day activity finishes in six weeks or seven.
  • The Hours and FTE rate sets, which are generated from the calendar’s period table and saved onto the project’s rate file.
Location: Admin > Projects > Edit Project > Calendar tab.
Prefer to watch? See How to Set Up Spread Profiles and Calendars for a video walkthrough.

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Prerequisites

  • Your account must have administrative access to the project.
  • The project needs its Start Date and Finish Date set, along with a resource file and a rate file. All five are shown read-only at the top of the tab for reference.

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Creating a calendar

Click Add Calendar to open the form. Click Generate Calendar to build the period table from those settings.
Generate Calendar rebuilds the period table. Running it again on an existing calendar recreates its periods and the Hours and FTE values derived from them. Use it when you intend to rebuild, not as a way to refresh the display.

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Calendar Periods

Once generated, the Calendar Periods tab shows one row per month: A total row is pinned to the bottom with the calendar’s overall working days and hours. Because month lengths and holidays differ, expect the per-month working days to vary (typically 20 to 23 on a Monday to Friday calendar). A Labels tab sits alongside Calendar Periods for custom period labels, where your organization reports on named periods rather than raw month names.

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Holidays

The Holidays panel sits beside the period table.
  1. Pick a Holiday Date.
  2. Tick Is Yearly Holiday if the date should repeat every year the calendar covers.
  3. Click Add Holiday.
The list keeps a running count in a badge, and Delete All clears every holiday at once. A holiday removes one day from the Working Days count for the period it falls in, which is what makes simulated durations step over it.
Add holidays before generating, or regenerate afterward. The period table is built from the settings as they stood when you clicked Generate Calendar, so holidays added later are not reflected until it is rebuilt.

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Saving rate sets

Save Hours Rate Set and Save FTE Rate Set write the generated column values into a named rate set on the project’s current rate file. You are prompted for a rateset name, which must be unique for that rate file.
Choosing an existing rateset name deletes and recreates every rate in that rateset to match the generated table. A confirmation step appears before the overwrite happens.
Click Save or Save & Close to store the calendar itself.

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Which calendar gets used

A project can hold more than one calendar, so the simulation picks by the Set As Default flag. If no calendar is marked as default, or the project has no calendars at all, the schedule simulation falls back to a standard five-day work week (Monday to Friday) with no holidays.
The fallback applies just as much when calendars exist but none is flagged as default. Building a calendar is not enough on its own; if you want holidays and a non-standard work week to affect simulated finish dates, one calendar must be set as the default.

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Where the calendar is used next

  • Schedule simulation: see the Risk Analysis guide for how durations are sampled and stepped.
  • Rate sets: the saved Hours and FTE rate sets become selectable on the project’s rate file. See Rates.