NET – No Earlier Than

NET, or “No Earlier Than,” is a time constraint used to define the earliest start date for tasks in various domains like project management and aerospace. It ensures orderly progress and efficient use of resources, with deviations potentially leading to delays and increased costs.


NET specifies the earliest possible date an event or activity can start or occur. It sets a lower-bound time constraint.


To enforce a sequence of events and ensure that dependencies are met before an activity can commence.

Context of Use

  • Project Management: Critical for defining project timelines and sequences.
  • Manufacturing: Used to schedule the production line.
  • Space Missions: Helps in coordinating the complex interplay of variables like launch windows.


An event with a NET date often relies on prior events being completed or resources being available.

Time-Resource Optimization

NET is part of optimizing the allocation of resources over time. It works in tandem with other time-related parameters like deadlines or “No Later Than” (NLT) constraints.

Constraints and Variables

External and internal factors, such as weather conditions in space launches or resource availability in project management, can affect the NET date.

Adjustment and Flexibility

NET dates may be adjusted as conditions change, but this often has a cascading effect on subsequent activities.

Impact on Cost

Poorly managed NET constraints can lead to resource wastage and cost overruns.

Global Perspective

  • Supply Chain: NET is critical in global supply chain management, affecting everything from production to delivery.
  • Regulatory Compliance: Different jurisdictions might have their own requirements that can affect NET dates.
  • Software Tools: Various project management and scheduling software have features to set and track NET and other time constraints.