How This Calculator Works
Enter the boat's price, your down payment, any trade-in, your state's sales tax rate, and typical fees, plus the rate and term your lender quoted. This calculator finances the sales tax and fees into the loan by default — the way most boat buyers actually pay them — then runs the same amortizing-loan formula lenders use to produce your monthly payment. Switch to "Solve for Max Boat Price" if you'd rather start from a monthly budget and work backward to the highest boat price that budget can support.
The Loan Payment Formula
This is the standard fixed-rate installment loan formula used across auto, boat, and personal lending. With n as the number of monthly payments:
Loan Amount = Boat Price + Sales Tax + Fees − Down Payment − Trade-In
Monthly Payment = Loan Amount × r ÷ (1 − (1 + r)−n)
where r = monthly interest rate = APR ÷ 12
There's no shortcut around amortization: some of every payment goes to interest (calculated on whatever balance remains that month) and the rest reduces principal, with the interest share shrinking and the principal share growing every month — see the year-by-year schedule above for the exact breakdown on your own numbers.
Down Payment: How Much Should You Put Down?
Most marine lenders ask for 10% to 20% down, with 10% being the single most common figure quoted across major boat lenders — though very well-qualified borrowers occasionally qualify for 0% down, and larger, older, or higher-risk boats sometimes require 20% or more. A bigger down payment does three things at once: it lowers your monthly payment, it reduces total interest paid over the life of the loan, and it reduces the odds of ending up "underwater" — owing more than the boat is worth — in the loan's early years, when depreciation is often fastest.
Loan Terms: Why Longer Isn't Always Better
Boats are financed more like a second home than a car — secured marine lenders commonly offer terms of 10 to 20 years even on mid-sized boats, well beyond typical auto loan terms. A longer term meaningfully lowers the monthly payment, which is why it's tempting, but it also stretches out interest payments and increases the total interest paid substantially. Try a few different term lengths in the calculator above and watch the "Total interest paid" row, not just the monthly payment — the gap between a 10-year and 20-year term on the same loan amount is often tens of thousands of dollars.
Secured vs. Unsecured Boat Loans
A secured boat loan uses the boat itself as collateral, similar to how a mortgage uses the home or an auto loan uses the car — the lender can repossess the boat if you default, which lets them offer meaningfully lower rates in exchange for that reduced risk. An unsecured boat loan is really a personal loan by another name: no collateral required, often faster approval, but a much wider and generally higher interest rate range, since the lender is taking on more risk with nothing to repossess. Unsecured loans also typically cap out around 7 years, while secured marine loans commonly stretch to 15 or 20 years for larger purchases.
Current Boat Loan Rates
As of mid-2026, well-qualified borrowers on secured boat loans are generally seeing rates in the 7% to 10% range, with the very best offers for excellent credit and large down payments starting closer to 6.5%. LendingTree's own rate data put the average secured boat loan rate at roughly 8.4% as of late 2025. Unsecured boat loans (personal loans) span a much wider band — commonly 7% to 36% — since approval leans more heavily on credit score and income than on the boat itself. Rates for used or older boats also tend to run somewhat higher than for new ones, all else being equal.
What This Calculator Doesn't Cover
This tool assumes a fixed rate held for the full term — it doesn't model variable-rate boat loans, which some lenders offer and which can change your payment over time. It also doesn't include ongoing ownership costs like insurance, dockage or storage, fuel, and maintenance, which for a mid-sized boat can easily add several thousand dollars a year on top of the loan payment itself. Finally, sales tax rules for boats vary meaningfully by state — some tax the full price regardless of trade-in, some cap the tax at a maximum dollar amount, and a few states charge no sales tax on boats at all — so confirm your own state's specific rule rather than relying solely on this estimate.
Frequently Asked Questions
Why can boat loan terms run longer than typical auto loans?
Boats are often financed more like a secondary home than a car — secured marine lenders commonly offer terms of 10 to 20 years for larger boats, which lowers the monthly payment but meaningfully increases total interest paid over the life of the loan.
Does a longer term always make sense just because the payment is lower?
Not necessarily — try a few different term lengths and compare the total interest row, not just the monthly payment. Boats also depreciate, so a long loan term risks owing more than the boat is worth (being "underwater" on the loan) for years at a stretch.
What's the difference between a secured and an unsecured boat loan?
A secured boat loan uses the boat itself as collateral, similar to a mortgage or auto loan, and typically carries lower rates (roughly 7-10% for well-qualified borrowers in 2026). An unsecured boat loan is really just a personal loan by another name — no collateral, faster approval, but a much wider and generally higher rate range, commonly 7-36% depending on credit.
How much should I put down on a boat?
Most marine lenders ask for 10-20% down, with 10% being the most common single figure — though some lenders go as low as 0% down for very well-qualified borrowers, and larger or older boats sometimes require 20% or more. A bigger down payment lowers both your monthly payment and your total interest, and reduces the odds of owing more than the boat is worth.
Does sales tax get added to the loan, or paid separately?
Most boat buyers finance the sales tax into the loan rather than paying it separately out of pocket, which is what this calculator assumes. Fees work the same way by default, though you can uncheck "Finance fees into the loan" to pay them upfront instead and see how that shifts your monthly payment and cash due at signing. Some states also give a tax credit for a trade-in's value, reducing the taxable amount — check your specific state's rule, since this varies.
Can I use this calculator for a used boat?
Yes — the loan math is identical for new and used boats. The main real-world difference is the interest rate: lenders typically charge somewhat higher rates for older or used boats, so check current rates for the specific boat's age before finalizing your numbers.
This calculator provides estimates for general informational purposes only and is not financial advice. Actual loan terms, fees, and taxes vary by lender, state, and boat.