Salary includes Basic + DA+fixed commission on turnover of the company
for eg.
If a person get salary 240000/- per annuam and bifurcation of the same is basic 7000/- pm, hra 3500/- pm, DA 3000/- pm, transport allowance 800/- pm, special allowance 5700/- pm. he is paying rent 4500/- per month in metro city (like Delhi, Mumbai, Chennai) HRA Calculation is as given below:
1st Condition : Excess of Rent paid over 10% of Salary
3500-2000=1500/-
IInd Condition : 40% or 50% of salary
10000/-
IIIrd Condition: Actural HRA Received
3500/-
So least of the above three condition is Rs. 1500/- per month
hence you can get exemption for Rs. 18000/- per annum