Mortgage lenders determine your loan amount by running your finances through several independent filters, and the tightest filter sets the ceiling. Your income and existing debts, your credit score, your down payment, the loan program you choose, federal loan limits, and the property’s appraised value each produce their own cap on what you can borrow. The number you’re approved for is whichever of those caps comes out lowest. Knowing which one is binding for you is the fastest way to figure out how to borrow more.
Income and Existing Debt
The first and usually tightest filter is your debt-to-income ratio. Lenders compare your gross monthly income to your monthly debt payments and use the result to decide the largest housing payment you can carry. Two versions matter. The front-end ratio looks only at the projected housing payment — principal, interest, property taxes, and homeowner’s insurance — and most conventional lenders want it at or below 28% of gross monthly income. The back-end ratio adds everything else that shows up on your credit report: student loans, car payments, credit cards, and other recurring debt.
Federal rules put a hard ceiling on the back-end number. Under the Ability-to-Repay rule, a lender has to make a reasonable determination that you can afford the loan, and for loans that meet the “Qualified Mortgage” standard, back-end DTI generally cannot exceed 43%.1Federal Register. Ability-to-Repay and Qualified Mortgage Standards Under the Truth in Lending Act (Regulation Z) Some government-backed programs (FHA, VA) will go higher with compensating factors like large reserves or an excellent credit history, but 43% is where the math starts working against most applicants.
In dollars: if you earn $7,000 a month gross and already pay $500 a month on existing debt, 43% of your income is $3,010. Subtract the $500, and the lender will let your total housing payment reach $2,510. That payment has to cover principal, interest, taxes, and insurance, so the actual loan principal it supports depends on the interest rate you qualify for.
Credit Score and the Rate You’re Offered
Your credit score doesn’t cap your loan directly. It controls your interest rate, which then controls how much principal fits inside your DTI limit. Lenders use your credit report to price the risk that you’ll fall behind, a practice called risk-based pricing, and federal rules require them to notify you when your credit history produces less favorable terms.2eCFR. 12 CFR Part 1022 Subpart H – Duties of Users Regarding Risk-Based Pricing
A lower score means a higher rate, and often a higher mortgage insurance premium on top of that. Both raise the monthly cost per dollar borrowed, so the lender has to shrink the loan to keep you under the same DTI. A borrower with a 760 score can qualify for a rate roughly a full percentage point below someone at 660, and on a 30-year mortgage that gap can cut purchasing power by $40,000 to $60,000 on the same income. If credit is your binding constraint, raising your score before you apply is usually the quickest way to borrow more.
Down Payment and Loan-to-Value
The loan-to-value ratio measures what percentage of the property’s value the lender is financing. A higher LTV means more risk to the lender, so each loan program sets its own LTV ceiling, and that ceiling independently caps your loan regardless of what your income would otherwise support.
Conventional Loans
Conventional mortgages sold to Fannie Mae or Freddie Mac require private mortgage insurance whenever LTV exceeds 80%,3Fannie Mae. Provision of Mortgage Insurance which is why 20% down became the familiar benchmark. It’s not a floor, though. Fannie Mae offers 97% LTV options (3% down) for first-time buyers, including the HomeReady program for borrowers earning up to 80% of area median income.4Fannie Mae. 97% Loan to Value Options You pay PMI on those loans, but the barrier to entry is lower than most buyers assume.
FHA, VA, and USDA Loans
FHA loans allow LTV up to 96.5%, so the minimum down payment is 3.5% of the purchase price.5HUD. What Is the Minimum Down Payment Requirement for FHA On a $400,000 home, that’s $14,000. FHA loans carry a mortgage insurance premium that in most cases lasts for the life of the loan, which is one reason borrowers often refinance into a conventional loan once they’ve built equity.
VA purchase loans, for eligible veterans and service members, allow 100% financing with no down payment and no mortgage insurance, as long as the purchase price doesn’t exceed the appraised value.6Veterans Affairs. Purchase Loan USDA guaranteed loans offer the same 100% financing for eligible buyers in qualifying rural areas.7USDA. Single Family Housing Guaranteed Loan Program Both programs effectively take the down payment out of the equation and leave income, credit, and property value as the binding constraints.
Program Loan Limits
Even if your income, credit, and down payment would support a bigger loan, federal limits cap what Fannie Mae and Freddie Mac will purchase. For 2026, the baseline conforming limit for a single-family home is $832,750 in most of the country. In designated high-cost areas, the ceiling rises to $1,249,125. Alaska, Hawaii, Guam, and the U.S. Virgin Islands have a higher baseline of $1,249,125 and a ceiling of $1,873,675.8U.S. Federal Housing Finance Agency (FHFA). FHFA Announces Conforming Loan Limit Values for 2026
FHA loans have their own limits. For 2026, the FHA floor is $541,287 in standard-cost areas and the ceiling is $1,249,125 in high-cost areas.9HUD. HUD’s Federal Housing Administration Announces 2026 Loan Limits
Loans above the conforming limit are jumbo loans. Lenders keep these on their own books instead of selling them, so they underwrite tighter: expect to need a credit score of at least 700, a down payment of 20% or more, and substantial cash reserves. Jumbo rates typically run slightly higher than conforming rates, though the gap narrows for strong credit profiles. Crossing from a conforming loan into a jumbo isn’t just a bigger number — it’s a different approval process.
How Your Income Has to Be Documented
A high income only counts if the lender believes it will continue. Fannie Mae’s guidelines look for a reliable pattern of employment over the most recent two years, though a shorter history can work with compensating strengths like strong reserves or specialized education in a high-demand field.10Fannie Mae. Standards for Employment-Related Income For a W-2 employee with steady paychecks, documentation is straightforward: recent pay stubs and two years of W-2s.
Self-employed borrowers face more scrutiny. Lenders usually require two years of signed federal tax returns plus a year-to-date profit and loss statement. The income figure they use is your net income after business deductions, not your gross revenue, and that often lands much lower than business owners expect. Aggressive tax deductions can quietly reduce qualifying income enough to shrink the loan.
Variable Income
If a meaningful part of your pay comes from bonuses, commissions, overtime, or tips, lenders generally want at least a 12-month track record, with two years preferred. When that income has been stable or increasing, the lender averages your year-to-date earnings with the prior year’s figures. When it has been declining, the lender won’t count it unless the current level has clearly stabilized.11Fannie Mae. Bonus, Commission, Overtime, and Tip Income A single bad commission year can drag the two-year average down enough to meaningfully reduce the approved loan.
Reserves and Documented Deposits
Beyond the down payment and closing costs, lenders want to see money left over in your accounts after closing. These reserves show you can keep paying if something goes wrong. Two months of reserves is common on a standard conforming loan; jumbo loans and investment properties often require six months or more. Thin reserves can cause the lender to reduce the approved loan amount even when income and credit otherwise clear.
Every dollar you claim as available funds has to be documented. Under Fannie Mae guidelines, any single deposit above 50% of your total monthly qualifying income is flagged as a “large deposit” and must be sourced with a paper trail.12Fannie Mae. Depository Accounts Part of the reason is that lenders have to comply with the Bank Secrecy Act, which requires financial institutions to detect and report activity that could indicate money laundering or other financial crimes.13Financial Crimes Enforcement Network. The Bank Secrecy Act If you’re using gift funds or proceeds from selling another asset, get the paper trail together before you apply. Unexplained deposits are one of the most common reasons loans get delayed or downsized in underwriting.
The Property Appraisal
Everything above sets what a lender would lend to you in the abstract. The appraisal sets what the lender will lend on this specific property. Before closing, the lender orders an independent appraisal to confirm the home is worth what you’re paying. Appraisals have to conform to the Uniform Standards of Professional Appraisal Practice under rules established by the Financial Institutions Reform, Recovery, and Enforcement Act.14eCFR. 12 CFR Part 323 – Appraisals The appraiser compares the home to recent sales of similar nearby properties and produces a market value.
The lender then calculates LTV using the lower of the purchase price or the appraised value.15Fannie Mae. Loan-to-Value (LTV) Ratios If you’ve agreed to pay $400,000 but the appraisal comes in at $380,000, the lender treats the home as a $380,000 property. At 80% LTV, your maximum loan drops from $320,000 to $304,000. You’d need to cover the $16,000 gap in cash, negotiate the price down, or walk away if your contract includes an appraisal contingency.
Cash to Close
The approved loan amount is not the only number that has to work. You also need enough cash to cover closing costs on top of the down payment: lender fees, title insurance, prepaid property taxes and homeowner’s insurance, and an escrow cushion. Federal rules cap that escrow cushion at no more than one-sixth of the estimated total annual escrow payments.16Consumer Financial Protection Bureau. 1024.17 Escrow Accounts
Total closing costs typically run between 2% and 5% of the loan amount, with smaller loans carrying a proportionally heavier burden. On a $200,000 mortgage, expect roughly $5,000 to $8,000; on a $600,000 mortgage, the percentage drops but the dollar amount can still reach $8,000 to $12,000. If you’re already stretching to cover the down payment, closing costs can be the overlooked expense that forces a smaller loan than your income supports. Some programs let the seller contribute toward closing costs, and some lenders offer “lender credits” in exchange for a slightly higher rate — options worth looking at if cash-to-close is your binding constraint.
A Word on Stretching the Numbers
Because so much of the loan amount depends on self-reported information, lenders verify aggressively, and the penalties for false statements are severe. Making a false statement on a mortgage application is a federal crime under 18 U.S.C. § 1014, punishable by up to $1,000,000 in fines, up to 30 years in prison, or both.17Office of the Law Revision Counsel. 18 USC 1014 – Loan and Credit Applications Generally; Renewals and Discounts; Crop Insurance If your finances don’t support the loan you want, the better move is to address whichever filter is actually binding — pay down debt, build reserves, raise your credit score, or save a larger down payment — and apply again when you genuinely qualify.