OmniPlan 4 Reference Manual for macOS


The following is a list of terms specific to OmniPlan or project management that you’ll encounter throughout this manual, defined and listed in alphabetical order for easy reference.

Actual schedule

The actual schedule for a project, in contrast to a baseline schedule, is the way the project turns out in real life. Before you set a baseline for a project, its baseline and actual schedules are the same. After you set a baseline, further editing changes the actual schedule only.


Assigning a resource to a task means that the resource is expected to be working on that task throughout its duration. Assignment amounts are expressed as the percentage of the resource’s work time being spent on the task. Manage resource assignments on a per-task basis using the Assigned Resources inspector.


See linked file.

Baseline schedule

A baseline schedule, in contrast to the actual schedule, is the way a project is planned to proceed from a given point in time. Before you set a baseline for a project, the baseline and actual schedules are the same. After you set a baseline, further editing changes the actual schedule only. You can compare a baseline schedule and the actual schedule in the Gantt chart using the View > Baseline Comparison submenu.


A member of a task or resource group is considered the group’s child. This is terminology common to outlining software.


Both tasks and resources can have monetary costs. The total cost of a task is the sum of the task cost and the costs of the resources assigned to it. A resource can have either or both of a cost per use and a cost per hour.

Critical path

The critical path is the series of dependent tasks which, if any of their durations change, will cause the whole project’s duration to change. You can check the critical path with View > Gantt > Critical Paths or the Critical Path toolbar button. Critical paths can be charted to individual milestones as well as to the entire project duration; view a milestone’s critical path by selecting its checkbox in the Milestones inspector.


The relationship by which one task must start or finish before another task can start or finish. For example, the task Buy Paint must finish before the task Paint Fence can begin.


Duration, in contrast to effort, is how long a task takes to complete in actual working time. For example, a task which takes 4 hours of effort and is assigned to 2 resources (both at 100% units and efficiency) has a duration of 2 hours.


The measure of how much work a resource can get done in a certain amount of time. Efficiency can affect duration and effort: 100% efficiency means the resource can contribute 1 hour of effort for every hour of work; 50% efficiency means it can contribute 1 hour of effort for every 2 hours of work; and so on.


Effort, in contrast to duration, is how much work time a task takes to complete, considering all of the resources assigned to it. For example, a task which has a duration of 4 hours and has 2 resources assigned to it (both at 100% units and efficiency) has an effort requirement of 8 hours.

Elapsed Time

A measurement of actual time required by a task or as a buffer between tasks. Elapsed time is “actual” in the sense that unlike regular duration or effort, the value refers to a specific amount of calendar time in the world and is not calculated based on the project’s work hours. Elapsed time is used when creating tasks with an elapsed duration, and can be used when setting lead/lag time between tasks.


Equipment is a type of resource. It represents some kind of reusable asset, such as computer hardware. It can also be useful to consider things like meeting rooms to be equipment, if you need to balance their use between different tasks.
For equipment resources, units represent the percentage of the equipment’s time that is available for the project.
Equipment can have Efficiency, Cost per Use, and Cost per Hour values.

Gantt Chart

A Gantt chart is a chronological representation of the project, shown in OmniPlan on the right side of the Gantt View. Each task is represented by a bar, corresponding to a row in the task outline, and may be connected to other tasks by lines representing dependencies; the horizontal size and position of the bar indicate the expected duration and schedule for the task.

Gantt View

A mode of the project document window in which you create, edit, and examine tasks. It contains the task outline on the left and the Gantt chart on the right.


The level of precision with which tasks are scheduled, as set in the Timeline inspector. Tasks can be scheduled exactly, or with hourly or daily granularity settings. The amount of effort a task requires is preserved when changing granularity (put another way, granularity only affects scheduling).


Items in the task outline or the resource list can be grouped together. The members, or children, of the group appear indented from the group itself in the outline. In the Gantt chart, a task group appears as a bracket enclosing its members.


A task of flexible effort whose duration changes based on constraints imposed by tasks scheduled before and after it.


A sidebar with tools to inspect your current selection.
OmniPlan’s inspectors live on right side of the main window. You can click and drag on the inspectors’ left edge to hide them, offering more screen space for the main view; drag in from the right side of the window to reveal them if they’re hidden. Choosing Inspectors > Show/Hide Inspectors (Shift-Command-I) works to do this as well.
When you select an item in one of OmniPlan’s views, the app automatically switches to the inspector most relevant to the type of item selected.


A single row in one of the task outlines or the resource list. General outlining commands like Expand and Collapse in the View menu and Indent and Outdent in the Structure menu work on items in any outline.

Lead Time

Lead time is a duration you can put on a dependency to mean that some amount of time is needed between the two tasks involved. For example, a Start→Start dependency with a lead time of 1 day means that after the first task starts, the second task can start one day later.
Lead time can be negative; for instance a Finish→Start dependency with a –2 hour lead time will allow the second task to start once the first task is 2 hours from completion.
You can set up lead time by typing a duration (such as +3w or –2d4h) either at the end of a dependency code in the Dependents or Prerequisites column of the task outline, or in the Dependencies inspector.
Lead time can also be a percentage of the predecessor task’s duration; for example you could enter 100% for a lead time exactly as long as the task it comes after.


Leveling the project, or leveling resources, means automatically rearranging the project to make sure the resources are being used as efficiently as possible. This means not allowing a resource to be assigned at more than 100% of its available units at any time, and finding the best order for resources to work on tasks in order to complete them more quickly.
Newly created projects can be set to automatically level resources as they are allocated to tasks. You can disable automatic leveling in the Project menu.
When not leveling automatically, you should level your project after making changes like updating task completion or changing resource assignments.

Linked File

A linked file is a representation in OmniPlan of a file somewhere on your computer. You can link files with Edit > Add Link To File to the project as a whole, to a task, or to a resource, and manage linked files for any of these with the Custom Data Linked Files inspector.


Material is a type of resource, representing consumable supplies.
For material resources, Units represent how many of the resource are being used throughout the project. This value updates as the resource is assigned to more tasks.
Material resources can have Cost per Use values, but not Cost per Hour values.


A milestone is a type of task that has no duration and requires no effort. Its purpose is to mark an important point in the project timeline. Based on dependencies and work schedules, a milestone may shift in time; you can keep track of your project’s milestones in Gantt View and the Milestones inspector.

Monte Carlo Estimation

The Monte Carlo simulation method uses random sampling based on a spread of values to estimate probable outcomes—in the case of OmniPlan Pro, the likelihood that your project or milestone will reach completion on time. When a simulation is run, hundreds of randomized possible outcomes are considered, and the average result is reported as a percentile of confidence that the milestone will be reached on a given day.
Because the estimate data used is randomized across a range of possible values, running multiple Monte Carlo simulations on the same data set will generate slightly different results each time. However, the number of iterations in a single simulation is high enough to eliminate grossly inaccurate outliers.

Network View

A mode of the document window that describes a project as a network diagram—a web of task nodes connected by dependencies. Unlike a Gantt chart, a network diagram deemphasizes project chronology in favor of a clear, evident depiction of the relationships between tasks.


A group is considered the parent of all its members. This is terminology common to outlining software.

Project Outline View

A mode of the document window in which you can create, edit, and examine tasks. It contains a task outline that spans the entire window, providing a more data-rich view with as many custom columns as possible.


When a project is publishing information about itself (a feature of OmniPlan Pro), it is telling other projects in a shared server repository what resources assigned to it are up to. If a resource is shared between projects (as indicated by an identifying email address), the load on that resource indicated by all publishing projects is taken into account when leveling across projects subscribing to the repository.


Resources are the people and things needed to get a project done. Resources are listed in the resource list, and can be assigned to tasks. The three types of resources are Staff, Material, and Equipment.

Resource load

A resource’s load is the amount of effort it is assigned to do at various times throughout the project. If a resource is assigned at more than 100% of its availability all at once, it is said to be overloaded or overutilized. Resource leveling tries to alleviate overload of resources. You can see each resource’s load in the resource timeline with View > Timeline > Resource Loads.

Resource timeline

On the right side of the resource view is a timeline of the tasks assigned to each resource. It provides a more vertically-compressed, resource-oriented look at the project.

Resource View

The mode of the document window in which you create, edit, and examine resources and schedules. It contains the resource list on the left and the resource timeline on the right, as well as calendars for normal working hours and custom hours.


Also known as float, in project management terminology slack refers to the amount of time a given task can be deferred until its duration to completion conflicts with the beginning of a subsequent dependent task (thereby causing a delay). Free slack refers to slack specific to a task and its successor, while total slack refers to a sum of all free slack in the project up to completion. Both values can be displayed as columns in Gantt View.


Staff is a type of resource, representing people who work on the project.
Staff units are measured as percentages. A person who is fully available to the project has a units value of 100%; someone who is spending part of their working hours on other projects would have lower available units. Note that this is not the same as having fewer working hours (which can be set in the Resource view), or being less efficient (which can be set in the Resource Info section of the Resource inspector).
Staff can have Address, Efficiency, Cost per Use, and Cost per Hour values.


When a project is subscribing to a shared server repository (a feature of OmniPlan Pro), it is on the lookout for resource load data being published by other projects. When leveling loads, a subscriber will adjust resources based on usage information received from the published projects.

T day

The first day of a project that has an undetermined start date. Until the start date is set, all dates are represented by an amount of time after T day, such as T+2w 1d.


An item of work that needs to be done for the project to progress. A task is represented by a row in the task or project outline, and by a corresponding task bar in the Gantt chart.


A template is a file you can use as a starting point for new documents, or (with OmniPlan Pro), there are also report templates, which are used for creating a HTML-based report of a project.


Units measure amounts of resources in various contexts. For staff and equipment resources, the units value is a percentage representing how much of the resource’s effort is available to be assigned to tasks in the project. For material resources, the units value is a number representing the physical quantity of the material used by tasks in the project.


Variance is the amount of time by which the actual schedule differs from the baseline schedule.


A violation is some sort of problem in the project that prevents it from working out properly. Violations can be resolved using the Violations Window.