Bridge Loan Calculator

Background.

A bridge loan is a form of short-term financing used primarily by homeowners who need to purchase a new property before selling their current one. Unlike a conventional thirty-year mortgage, which amortizes principal and interest over decades, a bridge loan typically matures within six to twelve months and is secured by the equity in the borrower's existing residence. The calculator below computes the full cost of this temporary facility, including monthly interest-only obligations, upfront origination points, and the balloon principal repayment due at maturity.

Borrowers seek bridge loans when they face contingent purchase agreements or competitive seller markets that do not accommodate sale contingencies. In these scenarios, a buyer must present a non-contingent offer to be taken seriously, yet the down payment and closing funds are trapped in illiquid home equity. A bridge loan unlocks that equity, but it does so at a premium. Interest rates routinely run one to two percentage points above the prime rate, and lenders often charge origination fees of one to three percent of the loan amount. Because the loan is non-amortizing, the borrower makes no principal reductions during the term; the entire original balance falls due as a balloon payment when the underlying property sells or when the borrower refinances into permanent financing.

The cost structure matters because bridge loans are not merely expensive on an annualized basis; they also carry front-loaded fees that erode net sale proceeds. Origination points, appraisal fees, title insurance, and legal costs are typically paid at closing and are not refundable if the existing home sells faster than expected. Furthermore, most bridge lenders require a combined loan-to-value ratio of no more than eighty percent across the existing first mortgage and the new bridge lien. This means a homeowner with substantial debt already outstanding may not qualify for enough bridge capital to cover the next down payment. The calculator therefore helps borrowers determine not only whether they can afford the carrying cost, but also whether the liquid equity net of existing liens supports the requested loan size.

From a regulatory standpoint, bridge loans secured by a consumer's dwelling are subject to Truth in Lending Act disclosures if the term exceeds twelve months or if certain other conditions apply. However, many residential bridge products are structured as temporary financing with terms under twelve months, which may exempt them from full Regulation Z APR calculations. The Consumer Financial Protection Bureau has issued guidance clarifying that even exempt temporary financing must still provide clear cost disclosures. Borrowers should note that interest paid on bridge loans secured by a qualified residence may be deductible under IRS Publication 936, subject to the same aggregate mortgage interest limitations that apply to acquisition and home-equity indebtedness. The calculator does not model tax effects, but users should retain their closing disclosures for tax preparation.

Understanding the arithmetic of a bridge loan prevents the common mistake of comparing the stated annual rate to a conventional mortgage rate in isolation. A six-month bridge at nine percent with two points is materially more expensive than it appears because the origination fee is paid upfront on the full amount while the loan is outstanding for only half a year. The effective cost of credit annualizes higher than the stated rate. The scenarios built into this calculator expose that true cost by expressing both the interest carry and the fee burden in absolute dollars, allowing an apples-to-apples comparison against alternatives such as home equity lines of credit, securities-backed lines, or simply negotiating a longer closing timeline on the purchase.

What is bridge loan calculator?

A bridge loan—also called swing financing or gap financing—is a short-term debt instrument collateralized by real estate. In residential contexts, the underlying security is almost always the borrower's current primary residence. The loan's purpose is to supply liquidity for a down payment or cash closing on a new home before the sale of the existing home generates proceeds. Maturities range from thirty days to thirty-six months, with six months being the most common structure in the United States.

Bridge loans are typically structured as interest-only debt with a balloon payment of the full principal at maturity. The borrower does not amortize the balance. Monthly payments cover only the accruing interest, calculated on a simple-interest basis against the outstanding principal. Lenders underwrite these loans based on the equity cushion in the collateral property and the borrower's ability to exit through sale or refinance, rather than on debt-to-income ratios used for permanent mortgages. Most lenders cap the combined loan-to-value ratio at seventy to eighty percent. Bridge financing is non-recourse in some commercial arrangements, but residential bridge loans are generally full-recourse obligations. Interest rates float above the prime index or are fixed at a spread over the lender's cost of funds. Origination fees, expressed in points where one point equals one percent of the loan amount, are deducted from proceeds or paid at closing.

How to use this calculator.

1. 01Enter the loan amount you expect to borrow against your current home equity.
2. 02Input the annual interest rate quoted by your bridge lender.
3. 03Set the loan term in months until you expect to sell your current property or refinance.
4. 04Add the origination fee as a percentage of the loan amount.
5. 05Include any additional closing costs such as appraisal, title, and legal fees.
6. 06Review the total cost of credit to compare this bridge loan against alternatives.
7. 07Check the balloon payment due to confirm you will have sufficient sale proceeds to repay the principal.

The formula.

The bridge loan calculator rests on simple-interest arithmetic because the loan does not amortize. The monthly interest payment equals the principal multiplied by the annual interest rate, divided by twelve. Mathematically, I_monthly = P × r / 12, where P denotes the loan principal in dollars and r denotes the annual interest rate expressed as a decimal. This formula assumes a standard thirty-day month and a 360-day year, which is the convention used by most private-money and portfolio lenders offering bridge products. The total interest paid over the term equals the monthly interest payment multiplied by the number of months: I_total = I_monthly × t, where t is the term in months.

The origination fee is calculated as a percentage of the principal: F = P × f, where f is the origination fee expressed as a decimal. One point equals 0.01. If a lender charges two points on a $400,000 bridge loan, the fee equals $8,000. This fee is typically paid at closing and is additive to any hard costs such as title insurance, escrow, or appraisal fees. The calculator sums the origination fee and the user-supplied closing costs to produce total upfront costs: C_upfront = F + C_closing.

Because the borrower makes no principal payments during the term, the balloon payment due at maturity equals the original principal: B = P. The total cost of credit—the figure the calculator highlights as the primary output—combines only the financing charges that are a direct function of the loan terms: interest plus origination. K_total = I_total + F. Closing costs are excluded from the cost of credit because they would be incurred even in an all-cash purchase, though they are included in the upfront cash requirement.

The calculator does not compute an annual percentage rate under Regulation Z because residential bridge loans under twelve months are often classified as temporary financing exempt from full APR disclosure. However, users can derive an approximate effective annual cost by dividing the total cost of credit by the principal and annualizing over the term: effective_cost = (K_total / P) × (12 / t). This yields a single percentage that captures both interest and points, making it easier to compare against a HELOC or margin loan. All monetary outputs are rounded to the cent using standard decimal arithmetic to avoid floating-point drift in JavaScript.

A worked example.

Frequently asked questions.

References& sources.

1. [1]CFPB (2024). "What is a bridge loan?"
2. [2]IRS (2024). "Publication 936: Home Mortgage Interest Deduction."
3. [3]Federal Reserve Board (2024). "12 CFR Part 1026 — Truth in Lending (Regulation Z)."
4. [4]OCC (2023). "Comptroller's Handbook: Residential Real Estate Lending."
5. [5]CFPB (2024). "What is a balloon payment?"