> ## Documentation Index
> Fetch the complete documentation index at: https://docs.glidepathcpm.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Calendars and Working Days

> Setting the project work week, holidays, and hours per day

# Calendars and Working Days

GlidePath uses a project calendar to determine which days count as working days. The CPM engine uses this calendar when calculating all task durations and dates -- a 5-day task on a Mon-Fri calendar schedules differently than on a 7-day calendar.

## Feature Spec Reference

**Module 5 -- Project Calendar**

## Accessing Calendar Settings

1. Open the **Project** menu in the top toolbar
2. Select **Project Settings**
3. Click the **Work Week** tab

Or navigate directly from the calendar icon in the project header.

## Work Week Configuration

### Setting Working Days

Use the checkboxes to specify which days of the week are working days:

| Day       | Default                 |
| --------- | ----------------------- |
| Monday    | Checked (working)       |
| Tuesday   | Checked (working)       |
| Wednesday | Checked (working)       |
| Thursday  | Checked (working)       |
| Friday    | Checked (working)       |
| Saturday  | Unchecked (non-working) |
| Sunday    | Unchecked (non-working) |

Uncheck any day to mark it as non-working. GlidePath will automatically skip those days when calculating task durations and scheduling start/finish dates.

**Example:** A 5-day task starting Monday on a Mon-Fri calendar finishes Friday. The same task starting Thursday finishes the following Wednesday (skipping Saturday and Sunday).

### Hours Per Day

Set the number of hours in a working day (default: 8). This affects:

* Duration display when showing hours instead of days
* Resource work calculations
* Lag values entered in hours

Valid range: 1-24 hours.

## Holidays and Non-Working Days

### Adding a Holiday

1. In the **Holidays** section of the Work Week tab, click **+ Add Holiday**
2. Enter a name (e.g., "Labor Day")
3. Select the date from the calendar picker
4. Click **Save**

The holiday is added to the list and GlidePath will skip that date in all scheduling calculations going forward.

### Removing a Holiday

Click the **Delete** (trash) icon next to any holiday in the list.

### Recurring Holidays

At this time, holidays must be entered individually for each year. If your project spans multiple years, add each holiday occurrence separately.

## How Calendar Changes Affect the Schedule

When you change the work week or add/remove holidays, GlidePath immediately recalculates the entire schedule:

* Tasks that fell on newly non-working days shift to the next working day
* Total project duration may increase or decrease
* The critical path is recalculated

**Important:** Always review the schedule after calendar changes to confirm that task dates shifted as expected.

## Resource Calendars

Individual resources can have their own calendars (vacation days, different shifts). When a resource is assigned to a task, the task's effective calendar is the intersection of the project calendar and the resource's calendar.

See [Resources and Assignment](/task-advanced/01-resources-assignment) for how to set resource-specific calendars.

## Calendar Impact on CPM

The CPM engine respects the project calendar during both the forward pass and backward pass:

* **Duration:** Task duration is measured in working days, skipping non-working days
* **Lag values:** Lag values entered in days are also measured in working days
* **Float:** Float values shown in the Float column represent working days of scheduling flexibility

## Screenshot

<img src="https://mintlify.s3.us-west-1.amazonaws.com/glide-path/assets/screenshots/04-02-calendarproject-settings-dialog.png" alt="Calendar and Project Settings Dialog" />

*Project Settings showing Work Week checkboxes and the Holidays section.*

***

## Next Steps

* [Automatic Scheduling](/scheduling/03-automatic-scheduling)
* [Constraints Deep Dive](/scheduling/04-constraints-deep-dive)
* [CPM Fundamentals](/scheduling/01-cpm-fundamentals)