Compare dealer financing, a 401(k) loan, liquidated investments, or a hybrid plan to see which car-buying option actually costs you the least.
The monthly payment doesn't tell the full story. Dealer loan interest, the opportunity cost of pulling money from a retirement account, and the capital gains taxes triggered by selling investments all affect your real out-of-pocket cost in ways that only show up when you model them side by side. This calculator does that math for you.
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Traditional auto loan
Finance through a dealer, bank, or credit union at a fixed rate over 36–84 months. Your investments stay untouched, but you pay interest to a third party. Often includes manufacturer rebates that can change the math significantly.
Borrow from your retirement plan
Borrow up to 50% of your vested balance (max $50,000) and repay yourself with interest. No credit check, no lender. The cost is the investment growth you forgo while the money is out of the market.
Sell from a taxable brokerage
Pay cash by selling holdings in a taxable account. No loan interest — but capital gains taxes on any appreciation, and that capital is no longer compounding.
Partial liquidation + loan
Finance long enough to capture a dealer rebate, then pay off the balance with a 401(k) loan or cash. Balances interest cost, tax exposure, and opportunity cost.
Read the full financing guide for a detailed explanation of each method, or see the methodology for the exact formulas used.