Halstead Complexity - Difficulty

The Halstead Complexity Difficulty calculator computes the difficulty to write or understand the program. 

INSTRUCTIONS: Enter the following:

• (N₂) Total number of operands
• (η₁) Number of unique operators
• (η₂) Number of unique operands

Halstead Complexity Difficulty(D): The calculator returns estimated difficulty in a software project.

The Math / Science

The formula for Halstead Complexity Difficulty is:

D = η₁ / 2 + N₂/ η₂

where:

• D = Halstead  Complexity Difficulty measure
• N₂ = Total number of Operands
• η₁ = Number of unique Operators
• η₂ = Number of Unique Operands

Definitions

• Operators are functions such as addition (+), subtraction (-), division (÷), multiplication (x).
• Operands are the values used in conjunction with operators.

In the example, (7x3)-13, the operators are the multiplication (x) and subtraction (-), of which there are two, and the operands are 7, 3, and 13, of which there are three.  Let's do a code example.

m = sqrt(x^2 + y^2 + z^2)

x = x/m

y = y/m

z = z/m

In the code above, the Total Number of Operands is 9: x, y, z, x and m, y and m, y and z.  The Unique Number of Operand are four (4), x, y, z and m.  The number of unique operators are four: sqrt(√), square (^2), addition (+) and division (/).  Using the Halstead Complexity Difficulty Measure:

      D = 4/2 + 9/4 = 4.25

Halstead Complexity Calculators

• Volume of Code
• Estimated number of delivered software bugs
• Difficulty of Code
• Time to Develop Code