From what part of income should someone take savings?

what otherwise would be fixed expenses

gross income, before other deductions

what otherwise would be discretionary income

gross income, along with other deductions

I believe the answer is: what otherwise would be discretionary income

Discretionary income refers to the remaining amount of income after being deducted by essential needs such as foods and rents along with tax income deduction.

The ideal amount for Discretionary income for average workers should be 20% or more from the total income.