Home Equity Loan vs. Auto Loan Calculator: Compare Costs

Home Equity Loan vs. Auto Loan Calculator: What the Comparison Measures

A home equity loan is a second mortgage secured by your house, usually paid out as a lump sum with a fixed rate. Financing an automobile is secured by the car itself. Because a house tends to appreciate while a car tends to depreciate, lenders often quote a lower rate on the equity side. A lower rate does not automatically mean a cheaper purchase, though, because the home equity route can add closing costs and tempts many borrowers into a longer repayment term. This calculator weighs all of that together and returns one number for each path: what you pay out of pocket from the day you buy until the final payment. Try the rv loan calculator to run your own numbers — everything is calculated in your browser and nothing you enter is stored or sent anywhere.

Monthly Payment Formula

Both loans are amortizing, so each monthly payment comes from the same standard equation, where \(P\) is the loan amount, \(r\) is the annual rate divided by 12, and \(n\) is the number of months:

$$M = P \times \frac{r}{1 - (1 + r)^{-n}}$$

Multiply \(M\) by \(n\) to get the total of all payments, then subtract \(P\) to isolate the interest you pay. For the home equity side, add the up-front costs to that total so the two choices are compared fairly.

Interest Rate on Each Loan

The tool asks for two separate rates: the auto loan interest rate offered by the dealer or bank, and the home equity interest rate from your lender. Your credit score and creditworthiness drive both numbers. Manufacturers sometimes run subsidized promotional rates on new vehicles to move inventory, and those offers frequently beat a home equity quote, but buyers with weaker credit may not qualify for them. A used car purchase, or any used vehicle bought from a private seller, often carries a higher APR, and both offers remain subject to credit approval, so run the comparison with the actual quotes in hand rather than averages.

Inputs for Your Home Equity Loan Payment Calculator

Every field in this home equity loan payment calculator maps to a real line on a purchase contract or a lender's disclosure. Fill each one in with quoted figures, not rough guesses. The free lease vs cash calculator is free to use with no sign-up, and works on desktop and mobile.

Total Purchase Price, Cash Down and Rebates

Start with the total purchase price before tax, including options and destination charges. Then subtract any cash down payment and manufacturer rebates. The larger your down payment, the smaller the loan amount you need to borrow, which shrinks the payment on either path.

Trade Allowance and Amount Owed on Trade

The trade allowance is what the dealer credits you for your current car. If you still owe money on it, enter the amount owed on trade as well; that outstanding balance is rolled into the new financing. A trade-in can also lower the sales tax you owe, depending on where you live.

Sales Tax and Trade-In Rules

Enter your local sales tax rate and tell the tool whether your state taxes the full price or only the price after the trade-in. A handful of states, including California, Hawaii and Michigan, allow no trade-in deduction, while a few others charge no sales tax on vehicle purchases at all. The same tax rate applies to both loans, so it raises the amount financed equally and never changes which option wins.

Closing Costs and Fees

Two kinds of up-front charges matter here:

• Auto fees: title transfer and any other charges due at delivery.
• Home equity closing costs: appraiser fees, points and miscellaneous lender charges. These raise the true price of the equity route even when its quoted rate looks lower.

Worked Example: A $38,460 Car Financed Two Ways

Suppose you are buying a car with a total purchase price of $38,460 before tax. You put $4,200 down, the dealer gives a $6,150 trade allowance, and you owe nothing on the trade. Sales tax is 6.4% on the price after the trade-in, and title fees are $215.

Sales tax is ($38,460 − $6,150) × 6.4% = $2,067.84, so the amount to finance is $38,460 + $2,067.84 + $215 − $4,200 − $6,150 = $30,392.84. Use the same loan term for both so the comparison stays fair. The dealer offers 7.89% for 60 months. Your lender offers a home equity loan at 8.45% for 60 months with $780 in closing costs.

Reading the Result

Treat each estimated payment as a quote rather than a guarantee, and expect any home equity loan calculator to show the same pattern when the rate gap and fees are this size. In this case the dealer offer wins by $1,269.90 over the five years. The home equity quote has the higher rate and adds closing costs, so nothing in it compensates for the extra expense. Notice also that the monthly payment is only $8.16 higher, which is why comparing the monthly figure alone would hide most of the gap.

The Break-Even Home Equity Interest Rate

Run the calculator again with lower home equity rates and the picture flips. With the same $780 in closing costs and the same 60-month term, the two paths cost the same at a home equity rate of about 6.99%. Anything below that makes the second mortgage cheaper; anything above it favors the dealer.

How a HELOC Differs From a Fixed-Rate Home Equity Loan

Lenders offer two products under the equity umbrella, and the calculator's results only hold for the one you actually choose.

Draw Period and Minimum Payments

A HELOC, short for home equity line of credit, works like a revolving line of credit. During the draw period you borrow as needed and may owe only a minimum payment, such as the greater of $100 or 0.5% of the outstanding balance. That flexibility is useful for ongoing projects but invites interest-only habits when you are buying a single car. A HELOC rate is also commonly variable, whereas a fixed-rate home equity loan gives you fixed monthly payments and a clean amortization schedule.

Loan-to-Value Limits and Available Equity

Most lenders cap your combined borrowing at a share of your home value, often 85% loan-to-value (LTV). Subtract your current mortgage balance from 85% of the home's value to estimate your available equity. A $15,000 minimum borrowing amount is common, so a small car purchase may not even qualify for a HELOC. Whatever loan amount you enter on the equity side must fit within that limit, or the quote is only theoretical.

Pricing a Used Truck With a Car Loan Versus a HELOC

Dana Whitfield needs a work truck before spring. The one she wants lists at $27,845, her old pickup is worth $4,320 on trade, and she still owes $1,150 on it. She has $3,500 in savings for the down payment. Her local credit union has pre-approved a car loan at 6.49% for 48 months, while her bank offered a HELOC-style fixed advance at 7.35% with $595 in closing costs. She suspects the lower-rate line wins because her house has plenty of equity: $412,000 in value against a $268,300 mortgage leaves $81,900 under an 85% loan-to-value cap.

She opens the comparison tool and enters the price, $3,500 down, the $4,320 trade allowance and $1,150 owed on the trade, then a 7.2% sales tax applied after the trade-in and $184 in fees. The tool computes tax of $1,693.80 and an amount to finance of $23,052.80.

Then she enters both rates for 48 months. The car loan comes back at $546.59 a month and $26,236.31 in total payments. The HELOC advance is $555.78 a month, which is $9.19 higher, and with closing costs the total reaches $27,272.40. The comparison says the credit union is cheaper by $1,036.09.

Before accepting that, Dana tests her next move: asking the bank to waive the $595. With zero closing costs the HELOC total falls to $26,677.40, still $441.09 above the car loan. She also finds the bank's rate would have to reach about 5.32% to break even, far below anything her credit score earns today. Her decision is specific: sign the credit union papers, leave the $81,900 of available equity untouched, and keep her house out of a truck purchase that depreciates the moment she drives it off the lot.

Risks a HELOC Comparison Does Not Show

Rules of thumb in personal finance warn against using debt to buy depreciating assets. A car loses value every year, while the debt secured by your house stays put. If you fall behind and default on either your first mortgage or the second one, the house can go into foreclosure; a missed dealer payment risks repossession of the car instead. Equity borrowing usually goes to debt consolidation or home improvement, where the payoff justifies putting a lien on the house; a depreciating car rarely does. The calculator compares dollar cost only, not foreclosure risk.

Weigh these risks against the total-cost difference the calculator returns. If the gap between the two totals is small, the safer choice is usually to keep the house out of it.

Is the Interest Deductible? Tax Rules After 2017

Before the Tax Cuts and Jobs Act, interest on home equity debt was tax deductible for most borrowers. Since 2018, second mortgage interest counts as an itemized deduction only when the money builds or substantially improves the home that secures it. Buying a car does not qualify, so leave any interest deduction fields at 0% for this comparison. Even a cash out refinance keeps the deduction only for the portion spent on the home, so none of this comparison's tax fields should assume one.

When Each Option Makes Sense

Use the results to choose with a clear rule, not a hunch:

• Choose dealer financing when manufacturers advertise subsidized rates, when you want to protect your home, or when your credit score qualifies you for the lowest tier of auto financing, with no extra paperwork against your property.
• Choose a home equity loan when its rate is below your break-even figure, closing costs are modest, and you will pay it off quickly rather than stretching the term.
• Get pre-approved for both before you visit the dealership, so you can negotiate on price rather than the monthly figure.
• Rerun the calculator with fresh quotes if rates fall; the Federal Reserve's decisions move auto and mortgage rates in the same general direction.