# The Three Pillars of Task Scheduling: Work, Duration, and Resources

When you assign resources to a task, Microsoft Project calculates the task’s schedule by using the work, duration, and resources associated with the task. Typically, you enter values for two of these, and Microsoft Project calculates the third.

Work is the amount of effort, measured in time units (like hours or days), put into a task by a resource. The total work for a task is the sum of all those time units, no matter how many resources are assigned to the task. For example, if two people each work 8 hours to complete a task, the total work for that task is 16 hours.

Duration is the amount of time between the start and finish of a task. Microsoft Project calculates a task’s duration based on the number of resources and the amount of work assigned to it. For a typical task, the more resources you assign to it, the shorter its duration will be.

Resources are the people, equipment, office space, and so on that do — or facilitate — the work on a task. Using resources gives you further control over your schedule. For instance, if you want a task or the project as a whole to decrease in duration, you can add more resources.

©1996-1997 Microsoft Corporation. All rights reserved.