What determines how much a lender will offer you

The amount a lender will lend you depends on four things: your income, your debts, your credit score, and the size of your down payment. Lenders use these to calculate how much monthly payment you can afford without defaulting. Most lenders cap your total monthly debt payments—including the new mortgage—at 43% of your gross monthly income, though some go as high as 50% if your credit is strong and your down payment is large.

Your credit score matters because it determines the interest rate you'll pay. A higher score means a lower rate, which means a lower monthly payment on the same loan amount. A lower score means a higher rate and a higher payment, which reduces how much you can borrow before hitting that 43% debt ceiling. The difference between a 620 score and a 760 score can shift your borrowing power by $50,000 or more on the same income.

Your down payment also shifts the calculation. A larger down payment means you borrow less, which means a smaller monthly payment. It also means the lender takes on less risk, so they may offer you a better rate. A 20% down payment typically gets you better terms than a 3% down payment on the same house price.

Key Takeaways

  • Lenders typically cap your total monthly debt payments at 43% of your gross income, though this varies by lender and your credit profile.
  • Your credit score directly affects the interest rate you receive, which changes how much you can borrow before hitting the debt-to-income limit.
  • A larger down payment reduces the loan amount and often qualifies you for a better interest rate, increasing your borrowing power.
  • You can estimate your range by calculating 43% of your gross monthly income, subtracting your existing monthly debts, and dividing the remainder by your estimated monthly payment per $100,000 borrowed.
  • Pre-qualification from a lender gives you a specific number based on your actual financial profile, not a general estimate.

How lenders calculate your debt-to-income ratio

Your debt-to-income ratio (DTI) is the percentage of your gross monthly income that goes toward all monthly debt payments. Lenders calculate it by adding up every monthly payment you owe—car loans, student loans, credit cards, child support, and the proposed mortgage payment—and dividing by your gross monthly income before taxes.

If you earn $5,000 gross per month and your existing debts total $800 per month, you have $4,200 left. At a 43% DTI limit, your total debt payments can be $2,150. That means your new mortgage payment can be no more than $1,350 per month. Using a mortgage calculator, $1,350 per month at today's rates might buy you a $250,000 loan, depending on the interest rate and loan term.

Some lenders use a stricter measure called the front-end ratio, which counts only the mortgage payment itself against your income. This is typically capped at 28% of gross income. Others use the back-end ratio (the 43% figure), which includes all debts. Most lenders look at both and use whichever is more restrictive.

What your credit score means for borrowing power

A credit score between 620 and 639 typically qualifies you for a conventional loan, but at a higher interest rate—often 1% to 2% above what a 740+ score would receive. A score between 740 and 759 usually gets you a competitive rate. A score of 760 or higher typically gets you the best rates available.

The difference compounds quickly. On a $300,000 loan, a 6.5% rate costs about $1,896 per month. A 7.5% rate on the same loan costs about $2,098 per month—$202 more each month. That $202 difference means you can only borrow about $50,000 less at the higher rate before hitting your DTI ceiling. Improving your credit score before applying can directly increase how much you can borrow.

If your score is below 620, most conventional lenders will not work with you. You may still find options through FHA loans (which accept scores as low as 580) or state-specific first-time buyer programs, but these typically require a larger down payment or charge higher fees to offset the risk.

How down payment size affects your loan amount

A down payment is the cash you bring to the purchase. If you put down 20%, you borrow 80% of the home price. If you put down 3%, you borrow 97%. The larger your down payment, the smaller the loan amount, and the smaller your monthly payment.

Down payments also trigger mortgage insurance requirements. If you put down less than 20%, most lenders require you to pay private mortgage insurance (PMI), which protects the lender if you default. PMI typically costs 0.5% to 1% of the loan amount per year, added to your monthly payment. This extra cost reduces how much you can borrow before hitting your DTI limit. A 3% down payment with PMI might reduce your borrowing power by 10% to 15% compared to a 20% down payment.

FHA loans allow down payments as low as 3.5% and use mortgage insurance called an upfront mortgage insurance premium (UFMIP) plus an annual premium. VA loans and USDA loans may allow 0% down in some cases, though they have their own insurance or may provide fees built into the monthly payment.

The difference between pre-qualification and pre-approval

Pre-qualification is an informal estimate. You tell a lender your income, debts, and credit score (or they pull a soft credit check), and they give you a rough range of what you might borrow. This takes minutes and carries no obligation. It is useful for understanding your ballpark, but it is not a commitment.

Pre-approval is a formal review. The lender pulls your full credit report, verifies your income with recent pay stubs or tax returns, and confirms your debts by checking your credit file. They then issue a letter stating the maximum loan amount you can borrow, the interest rate you may have access to for, and the conditions (like a home inspection or appraisal). Pre-approval takes a few days and shows sellers you are a serious buyer.

Pre-approval does not lock in your rate or may provide the loan. The lender still requires a property appraisal, a final underwriting review, and a clear title search. But it gives you a real number based on your actual finances, not an estimate. If you are shopping for homes, get pre-approved before you make an offer.

Why your existing debts matter more than you think

Every monthly debt payment reduces how much mortgage payment you can afford. A $400 car loan, a $200 student loan payment, and a $100 minimum credit card payment total $700 per month. At a 43% DTI limit on $5,000 gross income, that $700 in existing debt leaves you only $1,450 for a mortgage payment instead of $2,150. That is roughly $150,000 less in borrowing power.

Paying down or eliminating debts before you apply for a mortgage can significantly increase your borrowing power. Paying off a car loan three months before applying might increase your approved loan amount by $30,000 to $50,000. This is one of the fastest ways to improve your position if your income is fixed.

Lenders count minimum payments on credit cards, not your actual balance. If you have a $10,000 credit card balance but only pay the $200 minimum, the lender counts $200 toward your DTI. Paying the card down to zero removes that $200 from the calculation, even though your income has not changed.

How to estimate your range before talking to a lender

Start with your gross monthly income—the amount before taxes. Multiply it by 0.43 to find your maximum total monthly debt payments. Subtract all your existing monthly debts (car payments, student loans, credit card minimums, child support). The remainder is your maximum mortgage payment.

Next, estimate your monthly payment per $100,000 borrowed. At a 7% interest rate on a 30-year loan, that payment is roughly $665 per month. At 6%, it is roughly $600. At 8%, it is roughly $734. Divide your maximum mortgage payment by the per-$100,000 figure to estimate your loan amount. Then add your down payment to find the home price you might target.

This is a rough estimate only. Your actual rate depends on your credit score, loan type, and market conditions. Your actual payment depends on property taxes, homeowners insurance, and HOA fees in your area, which vary widely. A lender's pre-approval will give you a precise number based on your real situation.

Frequently Asked Questions

Does getting pre-approved hurt my credit score?

A pre-approval requires a hard credit pull, which temporarily lowers your score by a few points. However, multiple mortgage inquiries within 14 to 45 days (depending on the credit scoring model) count as a single inquiry, so shopping with multiple lenders in a short window does not compound the damage. The impact is temporary and typically recovers within a few months.

Can I borrow more if I have a co-signer?

Yes. A co-signer's income and debts are added to the calculation, which increases your total allowable debt payments. However, the co-signer's own debts also count, so a co-signer with high existing debt may not increase your borrowing power much. The co-signer is legally responsible for the loan if you default.

What if my income varies month to month?

Lenders typically average your income over the past two years if you are self-employed or work on commission. Some require a two-year history of the income source. If your income is new or highly variable, lenders may use a lower figure or require additional documentation. Showing consistent income over time strengthens your position.

Does the interest rate change after pre-approval?

Pre-approval usually includes a rate lock period of 30 to 60 days. If you close within that window, you keep the quoted rate. If you close after the lock expires, rates may have changed. You can extend the lock, but lenders typically charge a fee. If rates drop, you may be able to refinance later.

Can I increase my borrowing power by paying off one debt before applying?

Yes. Paying off a debt removes its monthly payment from your DTI calculation, freeing up room for a larger mortgage payment. Paying off a $300 monthly car payment, for example, could increase your borrowing power by roughly $70,000 to $100,000, depending on your income and interest rates.