Applicable banks will assess your repayment capacity while deciding the home loan eligibility. Repayment capacity is based on your monthly disposable/surplus income, (which in turn is based on factors such as total monthly income/surplus less monthly expenses) and other factors like spouses income, assets, liabilities, stability of income etc. The main concern of the bank is to make sure that you comfortably repay the loan on time and ensure end use. The higher the monthly disposable income, higher will be the amount you will be you will be eligible for loan. Typically a bank assumes that about 55-70% of your monthly disposable/surplus income is available for repayment of loan. however some banks calculate the income available for EMI payments based on an individuals gross income and not on his disposable income.
The amount of the loan depends on the tenure of the loan and the rate of interest.