As Software Engineers, we have to face major questions from clients, Management, etc. That is Whats the time and Cost?

Estimating the cost of the project is one of the most challenging jobs for the Software Engineer. One of the best ways to calculate the cost of the project is COCOMO. COCOMO stands for the Constructive Cost Model. It is a Constructive Cost Model which is totally based on LOC (Lines of Code) the project estimation is done based on the total lines of codes required to develop the system. i.e. Size of the system define the cost of the project.

Co = Constructive

Co = Cost

Mo= Model

COCOMO = Constructive Cost Model

  1. Basic COCOMO model: It estimates the software in a rough and quick manner. It is mostly useful for small-medium sized software. There are three modes of development.
  1. Organic
  2. Semi Detached
  3. Embedded

We used these three different modes of development to calculate the project effort, development time, average staff size, productivity according to different criteria which are shown below.

Size 2 50 KLOC 50 300 KLOC 300 & Above KLOC
Team Size Small Size Medium Size Large Size
Developer Experience Experienced Developers Needed Average Experienced People Very Little Previous experience
Environment Familiar Environment Less Familiar Significant environment changes (Almost new environment)
Innovation Little Medium Major
Deadline Not Tight Medium Tight
Example Payroll System Utility Systems, DBMS Air Traffic monitoring, ATM


  1. Effort = a (KLOC)b person month
  2. Development Time = c (Effort)d months
  3. Average Staff Size = Effort / Development Time   persons
  4. Productivity = KLOC / Effort    KLOC/ Person-Month
Software Product Type a b c d
Organic 2.4 1.05 2.5 0.38
Semi-detached 3.0 1.12 2.5 0.35
Embedded 3.6 1.20 2.5 0.32

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