Software sizing

Software sizing is an activity in software engineering that is used to estimate the size of a software application or component in order to be able to implement other software project management activities (such as estimating or tracking). Size is an inherent characteristic of a piece of software just like weight is an inherent characteristic of a tangible material.

Background

Software sizing is different from software effort estimation. Sizing estimates the probable size of a piece of software while effort estimation predicts the effort needed to build it. The relationship between the size of software and the effort required to produce it is productivity.

For example, if a software engineer has built a small web-based calculator application, we can say that the project effort was 280 man-hours. However, this does not give any information about the size of the software product itself. Conversely, we can say that the application size is 5,000 LOCs (Lines Of Code), or 30 FPs (Function Points) without identifying the project effort required to produce it.