How to use this calculator
- Boat price: the agreed price, before tax and fees. Include the trailer and engine if they’re part of the deal.
- Down payment and trade-in value: both reduce the amount you borrow.
- Interest rate and loan term: the APR and the number of years (up to 20) from your loan offer.
- Under Sales tax, fees & start date, enter your sales tax rate, any state cap on boat sales tax, title and registration or dealer fees, and whether those costs are paid upfront or added to the loan. The start date sets the dates in the payment schedule.
You get the monthly payment, the amount financed, the total interest, the total cost of the boat, a balance chart and a month-by-month amortization schedule you can download.
The formula
The amount financed is:
The monthly payment follows the standard amortization formula, where r is the APR ÷ 12 and n is the number of months:
Sales tax is charged on the price minus any trade-in. If you enter a cap, the tax is the smaller of the two.
Worked example
You buy a $60,000 boat with $12,000 down. Sales tax is 6% and fees are $500, both added to the loan, which is 8.5% APR for 15 years.
- Sales tax: 6% × $60,000 = $3,600
- Amount financed: $60,000 + $3,600 + $500 − $12,000 = $52,100
- Monthly payment: $513.05 for 180 months
- Total interest: $40,249
- Total cost of the boat (price, tax, fees and interest): $104,349
Paying the $4,100 of tax and fees in cash instead lowers the payment to $472.67 and the interest to $37,082.
Payments by loan term
On the same $52,100 at 8.5%:
| Term | Monthly payment | Total interest | Total cost |
|---|---|---|---|
| 5 years | $1,068.91 | $12,035 | $76,135 |
| 7 years | $825.08 | $17,207 | $81,307 |
| 10 years | $645.97 | $25,416 | $89,516 |
| 12 years | $578.34 | $31,181 | $95,281 |
| 15 years | $513.05 | $40,249 | $104,349 |
| 20 years | $452.14 | $56,411 | $120,511 |
The payment falls more and more slowly as the term grows, while the interest keeps climbing. Going from 15 to 20 years saves about $61 a month but costs about $16,162 more in interest. Boats also tend to lose value over time, so on a long loan you can owe more than the boat is worth for years.
Interest rate matters too
The same $52,100 over 15 years:
| APR | Monthly payment | Total interest |
|---|---|---|
| 6.5% | $453.85 | $29,592 |
| 7.5% | $482.97 | $34,836 |
| 8.5% | $513.05 | $40,249 |
| 9.5% | $544.04 | $45,828 |
| 10.5% | $575.91 | $51,565 |
Each point of APR adds about $30 a month and more than $5,000 of interest over 15 years. Get quotes from a bank or credit union, as well as the dealer, before you buy.
Sales tax caps
Some states tax boats differently from cars. Florida caps the sales and use tax on a boat at $18,000, including any county surtax. On a $400,000 boat at 6%, the uncapped tax would be $24,000, so the cap saves $6,000. Enter the cap in the calculator to apply it. Other states have their own rules, exemptions or separate boat taxes, so check with your state’s revenue department.
Tips before you sign
- Budget for ownership, not just the loan. Insurance, storage or slip fees, maintenance, winterizing and fuel all come on top of the payment. The RV loan calculator includes these costs as optional inputs, and works the same way for a boat.
- Check whether the interest is deductible. IRS Publication 936 says a home includes a boat with sleeping, cooking and toilet facilities, so interest on a loan secured by such a boat may count as home mortgage interest if you itemize.
- Keep your debts in proportion. The debt-to-income ratio calculator shows how a new payment affects what lenders see.
For an unsecured loan to buy a boat, compare rates with the personal loan calculator.
Assumptions and limitations
The calculator assumes a fixed-rate, simple-interest loan with level monthly payments, interest accruing at APR ÷ 12 and payments rounded to the cent, with the last payment adjusted for rounding. Fees aren’t taxed. It doesn’t include insurance, storage, maintenance, a balloon payment, a variable rate or prepayment penalties.
Sources
- Florida Statutes (2026), Section 212.05(5), and Florida Department of Revenue, Tax Information Publication 10A01-07 (the $18,000 cap on boat sales tax)
- Internal Revenue Service, Publication 936: Home Mortgage Interest Deduction (for 2025 returns)
This calculator gives estimates for general information. Your lender’s disclosures show the exact payment and APR, and a tax professional can tell you whether the interest is deductible.
Frequently asked questions
How do I calculate a boat loan payment?
Start with the amount financed, which is the price plus any sales tax and fees you add to the loan, minus your down payment and trade-in. Then apply the standard loan payment formula with your APR and the number of months. Financing $52,100 at 8.5% for 15 years comes to $513.05 a month.
How long can you finance a boat?
Terms depend on the lender, the size of the loan and the age of the boat, and larger loans on newer boats tend to qualify for longer terms. This calculator handles terms from 1 to 20 years. Ask each lender for its maximum term and the rate that goes with it, since longer terms often carry higher rates.
How much does a longer boat loan cost?
A lot more interest. On $52,100 at 8.5%, a 10-year loan costs $25,416 in interest, a 15-year loan $40,249 and a 20-year loan $56,411. Going from 10 to 20 years lowers the payment by about $194 a month but more than doubles the interest.
Do you pay sales tax on a boat?
In most states, yes, at the state and local rate, and some states treat boats differently from cars. Florida, for example, caps the sales tax on a boat at $18,000. Enter your rate and any cap under "Sales tax, fees & start date," or set the rate to 0 if your purchase isn't taxed.
Is boat loan interest tax deductible?
It can be. IRS Publication 936 counts a boat as a home for the mortgage interest deduction if it has sleeping, cooking and toilet facilities, so a loan secured by such a boat may qualify as a main or second home. You have to itemize, and limits apply. Check with a tax professional.
How much should I put down on a boat?
A larger down payment lowers the payment and the interest, and keeps you from owing more than the boat is worth as it ages. Lenders set their own minimums. In our example, 20% down on a $60,000 boat leaves $52,100 to finance once tax and fees are added.
Updated November 2026. Results are estimates for educational purposes and depend on the inputs you provide.