The amount of money that is spent to produce something of value. In a task plan, a cost is the amount of money that is spent while finishing a task. For example, a resource's hourly billing rate or the cost of renting a tractor (a material resource) for a day. A cost can be associated with a task, a resource, an assignment, or a task plan.

There are three types of costs: fixed, per-use, and rate.

You can use a baseline to compare original costs to actual costs over the life of a task plan by comparing the variance between the original cost values and the actual cost values.