Personmåneder

Personmåneder is a unit of work used in project planning and estimation to quantify the amount of labor required for a task or project. The term, used in Danish and Norwegian contexts, denotes one person working full-time for one calendar month. In practice, a person-month is tied to the assumed number of working hours in a month, which varies by country and organization.

Calculation and example: Total effort for a project is calculated by summing person-months across the planned workforce. For example, three people working full-time for four months amount to twelve person-months. If two people work for two months at 80 percent utilization, the effort equals 3.2 person-months.

Uses: Personmåneder are used for planning staffing, budgeting, and scheduling, as well as for evaluating alternatives and tracking progress against estimates. They provide a high-level way to translate scope into required workforce and time.

Limitations: The concept assumes relatively constant productivity and does not capture variations in skill, ramp-up time, or downtime. It is not a precise calendar duration and does not directly correspond to cost, since wage rates and non-working days vary. The unit depends on the assumed average hours per person-month, which can differ across organizations.

Related terms: Person-days and person-hours offer finer granularity, while the concept of effort can be distinguished from actual calendar time when planning and monitoring projects. In practice, person-måneder are most useful for initial estimations and high-level resource planning.