Calculate space complexity of algorithms

Calculate space complexity of algorithms

Space Complexity:

Space complexity is about the amount of memory space required by an algorithm during the execution of a program or an algorithm.

Space Complexity of Algorithm  S(n) is the number of units of memory used by an algorithm as a function of data size

for any algorithm, memory is required for the following purposes:

  • To store program instruction,

  • To store constant variable,

  • To store variable values,

  • And for a few other things like function calls, jumping statement, etc.

How to calculate space complexity of algorithms:

S(P)= C+Sp

S(P): Space Complexity

C: Fixed Part (independent or constant)

Sp: Variable Part (Dependent character)


1) Algorithm abc(a,b,c)


return a+b+c*c(a+b)+4;


For every instance, 3 words are required  to store variable a, b, and c

S(P)= 3

2) Algorithm Sum(a[ ],n)



for i=1 to n do


return s;



To store a[n] = n words

To store n = 1 word

Tp store s and i = 2 words

So the S(p)= n+3