Balloon boat loans: how the payment and the final balance work

A balloon boat loan sets the monthly payment as if the loan ran longer than it actually does. When the term ends, whatever you still owe is due in one payment. As an example, $360,000 at 8.00% APR with payments figured over 20 years but due in 15 leaves a balloon of $148,506.89 at the end.

How the calculator models it

The calculator has two separate settings: Term, which is when the loan is due, and Payments figured over, which is the schedule used to set the monthly payment. When the two match, the loan pays off to zero. When “payments figured over” is longer than the term, the calculator works it in two steps:

1. Figure the monthly payment as if the loan ran the longer period. With P the loan, r the monthly rate and n the months, payment = P × r ÷ (1 − (1 + r)^−n).
2. Figure what’s still owed after the actual term of k months: balance = P × (1 + r)^k − payment × ((1 + r)^k − 1) ÷ r. That balance is the balloon.

The chart plate draws the balance year by year and marks the balloon in magenta, so you can see how much of the loan is still standing on the last day.

Worked example

This is the calculator’s default scenario. It’s an example, not an offer, and the rate is a placeholder, not a typical rate.

• Purchase price $450,000, down payment $90,000 (20%), so $360,000 financed
• APR 8.00% (monthly rate 0.6667%)
• Term 15 years (180 payments), payments figured over 20 years (240 months)
• No sales tax, fees or insurance included

Step one, the payment on a 240-month schedule: $3,011.18 a month.

Step two, the balance after 180 of those payments: $148,506.89, due at month 180.

Here’s the same loan paid off in full over the 15 years, for comparison:

	15-year term, figured over 20 (balloon)	15-year term, paid off in 15
Monthly payment	$3,011.18	$3,440.35
Total of 180 payments	$542,013.16	$619,262.55
Interest paid during the 15 years	$330,520.05	$259,262.55
Still owed at month 180	$148,506.89	$0

The balloon version saves $429.17 a month. Over 15 years it also pays $71,257.50 more in interest, and you still owe nearly $150,000 at the end. The payment is lower because less of each one goes to principal, so you pay interest on a bigger balance for longer.

To check the interest line yourself: of the $542,013.16 you pay in, $360,000 − $148,506.89 = $211,493.11 went to principal. The rest, $330,520.05, is interest.

What happens at maturity

When the balloon comes due you pay it from cash, from selling the boat, or with a new loan. The last two depend on things you can’t know when you sign.

A new loan depends first on the boat as it is then. In the example, a boat bought new is 15 years old when the balloon is due. Lenders’ published age rules start to bite there. Truist’s marine loan takes boats up to 15 prior model years. Trident Funding says boats “generally need to be 20 years old or younger.” DuPage Credit Union limits boats from 2019 and older to 60 months. U.S. Bank’s advertised refinance rate is for boats under four years old, and U.S. Bank doesn’t refinance Coast Guard documented vessels at all. (All from lender pages read October 24, 2026; links are on the lender terms page.)

It also depends on rates at the time. The rate on a new loan in 15 years could be higher or lower than yours, and nobody can tell you which.

Selling depends on what the boat is worth by then. If it sells for less than the balloon, the loan still has to be paid off, so you cover the difference in cash. We don’t publish resale or depreciation figures because we haven’t found a primary source for them; a marine surveyor’s valuation is the closest thing to a real number for a specific boat.

No lender we read publishes a balloon product

We read the boat loan pages of Navy Federal, Truist, M&T Bank, U.S. Bank, DuPage Credit Union, LightStream, Trident Funding, Southeast Financial and Intercoastal Financial Group on October 24, 2026. None of them publishes a balloon option. That doesn’t mean none will write one, only that it isn’t on their public pages. If you want one, ask, and ask these questions:

• Is the balloon a fixed dollar amount in the note, or whatever the balance is at maturity?
• Is there any right to extend or refinance at maturity, and on what terms?
• Does the rate differ from a fully paid-off loan of the same term?
• Is there a prepayment penalty if you pay down the balance early to shrink the balloon?

If a lender doesn’t offer a balloon, a longer fully paid-off term with no prepayment penalty gets you a similar low payment without a lump sum on a fixed date. Truist and DuPage both state they don’t charge prepayment penalties. See how long you can finance a boat for the published maximum terms.

Running your own numbers

In the calculator, set the term to when you’d want the loan due and “payments figured over” to the payment you can live with. Watch the balloon line and the magenta marker as you change them. Add your state’s tax from the sales tax guide if you plan to roll it in, since it raises the balloon too. When you have a structure you’d sign, ask lenders to quote it in writing, balloon included. Questions about it? Send us your numbers.