Before you shop for a boat, know the payment. Here is the formula, a worked example and a term comparison.
Updated November 2026
What goes into a boat payment
A boat loan is a fixed-rate installment loan in most cases. Four numbers drive the payment: the amount financed, the rate, the term and any fees. Run yours through the boat loan calculator, or use the steps below.
Step 1: Find the amount financed
Add sales tax to the price and subtract your down payment. For a $45,000 boat with 6 percent tax the total is $47,700. With $4,500 down, you finance $43,200.00. Check your state, since boat taxes and fees vary.
Step 2: Apply the payment formula
With an 8.5 percent rate, i = 0.085 / 12 = 0.0070833, and a 10-year term N = 120. The payment is $535.62. You repay $64,274.18, so interest is $21,074.18. In Excel use the PMT function: =PMT(8.5%/12,120,-43200).
How the term changes the cost
| Term | Monthly payment | Total interest |
|---|---|---|
| 5 years | $886.31 | $9,978.85 |
| 10 years | $535.62 | $21,074.18 |
| 15 years | $425.41 | $33,373.35 |
Stretching to 15 years cuts the payment by $110.21 but adds $12,299.17 of interest compared with 10 years.
Costs the loan does not cover
- Insurance, which is often required by the lender.
- Registration, docking or storage, fuel and winterizing.
- Maintenance and repairs, which tend to rise with the age of the boat.
- A trailer if you do not already have one.
Add these to your monthly budget before you decide how much to borrow. Compare with a general loan on the personal loan calculator, and see what extra payments do with the loan payoff calculator.
These are illustrations to help you plan, not financial advice.
Frequently asked questions
How do I calculate a boat loan payment?
Use Payment = L x i / (1 – (1 + i)^-N) or =PMT(rate/12,months,-loan) in Excel.
What is the payment on a $43,200 boat loan at 8.5% for 10 years?
$535.62 a month.
Is a longer boat loan term better?
It lowers the payment but increases total interest. Choose the shortest term that fits your budget.
Can I finance sales tax?
Often yes, but check with your lender.