The size of the construction loan you can get is set by whichever is lower: a loan-to-cost cap on your building budget, usually 80% to 90%, or a loan-to-value cap on the home’s projected finished worth, which runs up to 95% on many conventional construction-to-permanent loans and can reach 97% on some fixed-rate programs. On top of that ratio math, your maximum is bounded by the conforming loan limit (or the FHA or VA limit if you use a government-backed program), the appraiser’s estimate of the completed home, your debt-to-income ratio, your credit score, and your cash reserves. FHA construction loans require as little as 3.5% down, and VA construction loans require none.
The Two Ratios That Set Your Ceiling
Every construction lender runs two calculations and gives you the smaller result.
The loan-to-cost ratio measures how much of your actual build the lender will fund. It covers land, materials, labor, permits, and other hard costs. Most lenders cap LTC between 80% and 90%. On a $500,000 project with an 80% LTC cap, the lender funds up to $400,000 and you cover the remaining $100,000.
The loan-to-value ratio compares the loan amount to the appraiser’s projected market value of the finished home. If the finished home is projected to be worth $600,000 and the lender allows 80% LTV, your ceiling is $480,000 regardless of what the build actually costs. For conventional construction-to-permanent loans eligible for Fannie Mae purchase, LTV can run as high as 95% on a primary residence with an adjustable rate, and some fixed-rate programs allow up to 97%.1Fannie Mae. Eligibility Matrix Individual lenders often add overlays that cap LTV lower, often at 80% or 85%, based on property type, credit, or their own risk tolerance. Portfolio lenders keeping the loan on their books tend to be the most conservative.
Whichever ratio produces the smaller dollar figure wins. If LTC says $400,000 and LTV says $480,000, you get $400,000. If a low appraisal flips the numbers, LTV controls. LTV is often the binding constraint on custom builds because appraisals don’t always keep pace with high-end finishes that cost more than they add in resale value.
Program Dollar Limits
Favorable ratios don’t override the absolute dollar cap set by the loan program you use.
Conforming Loans
For 2026, the Federal Housing Finance Agency set the baseline conforming loan limit for a single-family home at $832,750 in most of the country, rising to $1,249,125 in designated high-cost areas.2Federal Housing Finance Agency. FHFA Announces Conforming Loan Limit Values for 2026 If your project needs more, you move into jumbo construction loan territory, which comes with higher credit score requirements, larger reserve demands, lower LTV caps, and a steeper rate premium. If your build is close to the conforming limit, running the numbers both ways can be worth the exercise.
FHA One-Time Close Loans
FHA construction loans allow a down payment as low as 3.5% of the appraised as-completed value for borrowers with credit scores of 580 or higher. Construction financing and the permanent mortgage close together, so you avoid a second set of closing costs. For 2026, FHA loan limits range from a floor of $541,287 in lower-cost areas up to $1,249,125 in high-cost markets.3U.S. Department of Housing and Urban Development. HUD FHA Announces 2026 Loan Limits Many FHA-approved lenders impose overlays above the FHA minimums. The 580 score is a technical floor; most lenders want 620 to 640. The property must be your primary residence, and you pay both an upfront mortgage insurance premium and annual mortgage insurance for the life of the loan.
VA Construction Loans
Eligible veterans and active-duty service members can finance construction with no down payment through a VA-backed loan.4U.S. Department of Veterans Affairs. Purchase Loan That 100% financing is the most generous option available. There’s no private mortgage insurance, though VA loans carry a one-time funding fee. The practical constraint is finding a lender willing to originate a VA construction loan, since fewer offer them than conventional or FHA products, and those that do often have tighter builder approval requirements.
What the Appraiser Does to Your Number
No matter what the ratios and limits allow on paper, the appraiser’s estimate of the finished home’s market value controls your LTV, and that often controls your loan. Construction appraisals are performed “subject to completion.” The appraiser reviews your blueprints, specifications, and proposed finishes, then compares the planned home against recent sales of similar properties in the area.5Fannie Mae. Requirements for Verifying Completion and Postponed Improvements That value becomes the denominator in every LTV calculation.
This is where many borrowers get surprised. You might budget $600,000 to build a home with imported tile and custom cabinetry, but if the appraiser decides comparable homes in the neighborhood sell for $550,000, your LTV is calculated on $550,000 and you cover the difference out of pocket. Expensive finishes that don’t move the needle on resale value are the classic trap. The appraisal doesn’t care what you spend; it cares what a buyer would pay.
Appraisals also expire. For most mortgage purposes, an appraisal must be performed within 12 months before the loan closes. If the original appraisal is more than four months old, the lender needs an update confirming the value hasn’t declined. A project that drags past its expected timeline can trigger a new appraisal, and if the market has softened, you may need to bring additional funds. Single-close construction-to-permanent loans are exempt from the standard appraisal age rules, but the lender still requires a completion report confirming the home was built as planned before the loan converts to permanent financing.6Fannie Mae. Appraisal Age and Use Requirements
What Your Own Finances Do to Your Number
Project math is only half of it. Lenders underwrite you personally, and three factors do most of the work.
Debt-to-Income Ratio
Your DTI compares your total monthly debt obligations, including the projected mortgage payment on the completed home, to your gross monthly income. For loans underwritten through Fannie Mae’s automated system, the maximum DTI is 50%. Manually underwritten loans start at a 36% cap and can stretch to 45% with strong credit and significant reserves.7Fannie Mae. Debt-to-Income Ratios A high DTI doesn’t just threaten approval; it directly limits loan size, because the lender works backward from the monthly payment you can afford to the principal that payment supports.
Credit Score
Construction loans generally require higher credit scores than standard purchases. Most lenders offering conventional construction-to-permanent financing want a FICO score of at least 680, though some go lower with compensating factors like a large down payment or low DTI. FHA technically accepts 580 for maximum financing, but lender overlays typically push the real minimum to 620 or above. A higher score opens up both a better rate and a higher LTV approval.
Cash Reserves
Lenders want to see liquid assets left over after your down payment and closing costs. Construction loans typically require anywhere from two to twelve months of housing payments in verified accounts. The exact amount depends on the loan program, property type, and your overall profile. Reserves matter more here than on a standard purchase because construction timelines slip, change orders happen, and lenders want confidence you won’t run dry mid-build.
Using Land Equity Instead of Cash
If you already own the lot, the equity in it can count toward your down payment. This is one of the strongest levers for increasing the effective size of your construction loan without bringing more cash. The lender appraises the lot at its current market value, and the difference between that value and any remaining balance on a land loan becomes your equity contribution.
Say you own a lot appraised at $100,000 free and clear. On a construction-to-permanent loan with a 10% equity requirement, that $100,000 satisfies the entire down payment on a project worth up to $1,000,000. You bring zero additional cash for the down payment itself, though you still need funds for closing costs and reserves. If you’re still paying off the land, only the equity portion counts. Most lenders offering construction-to-permanent financing accept land equity, but confirm this early because it affects how the loan is structured from the start.
The Contingency Reserve Changes the Math
Most lenders require a contingency reserve of 5% to 10% of the total project budget built into your financing plan. The reserve covers the inevitable surprises: poor soil conditions, material price increases, weather delays, change orders. On a $500,000 build, expect to set aside $25,000 to $50,000 for overruns.
The contingency affects your loan sizing because it increases the total project cost used in the LTC calculation. A project with a $500,000 hard budget and a 10% contingency has an effective cost of $550,000. If the lender caps LTC at 80%, your maximum loan against that figure is $440,000. Skipping or underestimating the contingency doesn’t save money. It just means you cover overruns from personal funds with no cushion.
Putting the Numbers Together
To estimate your own ceiling, work in this order. Start with the total project cost, including land, hard construction costs, and a contingency reserve of at least 5% to 10%. Apply the lender’s LTC cap to that figure. Separately, estimate the finished home’s appraised value based on comparable sales, and apply the LTV cap your credit and program allow. Take the lower of the two. Then check that number against the conforming limit (or the FHA or VA limit) for your area, and against what your DTI will actually support given your income and other debts. The smallest of those four figures is the realistic size of the construction loan you can get.