Home affordability calculator:
work back from your monthly budget

What home affordability really means

A lender's approval ceiling is not the same as an affordable home. Lenders test whether you can repay; you also need to live on what is left, keep saving and absorb a bad year.

Affordability therefore starts from your monthly cash flow, not the property price. Work out what you can pay each month without strain, convert that into a loan amount, then add your down payment to see what price range you can look at.

Lenders usually look at your fixed monthly obligations as a share of income, and the limit differs by lender, so ask yours. Passing that test only shows you can be lent the money. Your own budget decides whether the loan is comfortable.

The steps below run the usual home-loan calculation in reverse, from the EMI you can carry to the loan it supports.

The affordability formula

A quick shortcut: at 8.5% over 20 years, every ₹1 of EMI supports about ₹115 of loan, so ₹26,000 supports about ₹29.96 lakh. At 9.5% the multiple falls to about ₹107, and at 10.5% to about ₹100.

1. 1Take your monthly take-home pay, then subtract existing EMIs and fixed obligations.
2. 2Set the share you are willing to put into housing.
3. 3Subtract recurring home costs, such as maintenance and property tax, to get the EMI ceiling.
4. 4Apply the formula for a loan size, then divide by one minus your down-payment share for a price.

Example: ₹1,00,000 take-home and a ₹30,000 housing budget

Take a household with ₹1,00,000 take-home pay and ₹20,000 of existing EMIs and fixed obligations. It sets a housing budget of ₹30,000 a month. Of that, assume ₹4,000 goes to maintenance, property tax and insurance, leaving ₹26,000 for the EMI.

Existing EMIs matter as much as income. Clearing a ₹10,000 EMI before you apply frees that amount for housing, which supports about ₹11.5 lakh more in loan at the same rate and tenure.

After the ₹20,000 obligations and ₹30,000 housing budget, ₹50,000 remains for food, travel, savings and everything else. The housing budget takes 30% of take-home, and fixed commitments together take half.

It also helps to compare the total with your current rent. If you pay ₹18,000 in rent today and ownership would cost ₹30,000 a month, the extra ₹12,000 is the monthly price of owning, and it should buy you something you value.

How the housing budget changes the loan and price

The loan scales almost in line with the EMI, so each extra ₹5,000 in the housing budget supports about ₹5.7 lakh more in loan and about ₹7.2 lakh more in property price.

The down payment moves the price too. The same loan of about ₹29,96,000 supports a price of about ₹33.29 lakh with 10% down and about ₹42.80 lakh with 30% down. A bigger down payment buys more house, but it must come from savings that are not also your emergency fund.

How rate and tenure move the answer

Rising from 8.5% to 10.5% shrinks the loan the same EMI can service by about ₹3.9 lakh. Each one-point rise costs roughly ₹1.9 to ₹2.3 lakh of borrowing power at this budget, so a rate you can only just afford today is a rate you will struggle with if it moves.

A longer tenure raises the loan you can take, but it also raises the total interest you pay. Stretching to 30 years raises the loan by about ₹3.9 lakh over 20 years, while keeping you in debt for ten extra years.

Stress-test the plan before you commit

Test two things. First, a rate rise: a ₹30,00,000 loan at 8.5% over 20 years has an EMI of about ₹26,035. At 10.5% the same loan costs about ₹29,951, which is ₹3,917 more every month.

Second, an income dip. If take-home falls 20% to ₹80,000, the same ₹20,000 of obligations and ₹30,000 housing cost take 62.5% of it, not 50%. Check that you could cover the EMI from savings for at least six months if income stopped.

One-time costs need cash on top of the down payment. As an illustration only, if stamp duty, registration, brokerage and moving costs came to 7% of a ₹37.45 lakh home, you would need about ₹2.62 lakh extra. The real share varies by state and property, so ask for the figure before you sign.

Keep an emergency fund separate from your down payment. Six months of the fixed commitments in this example, ₹20,000 plus ₹30,000 a month, comes to ₹3,00,000. Using up your savings to reach a larger down payment can leave you exposed in the first year, when moving costs and repairs are highest.

Mistakes that stretch a home budget

Most affordability trouble comes from a small number of avoidable assumptions.

• Treating the maximum loan a lender offers as the amount you should borrow.
• Leaving out one-time costs such as stamp duty, registration, brokerage, interiors and moving.
• Counting gross salary instead of take-home pay.
• Forgetting maintenance, property tax and insurance, which recur every month or year.
• Choosing a long tenure only to qualify for a higher price, without checking the total interest.

If two people earn, base the plan on the steadier income and treat the other as a buffer. Also check how the lender caps the tenure against your retirement age, because a shorter permitted tenure raises the EMI for the same loan.

If saving 20% of take-home is also part of your plan, that is ₹20,000 a month, which leaves only ₹30,000 for everything else in the example. Count that before you settle on the housing budget.