Money

How much to put down

The honest answer is that it depends on what else the money has to do. But the arithmetic is not a matter of opinion, so here is one deal branched three ways and followed all the way to the end — including the part where the answer is "less than you think."

Drive Thru Deals · September 17, 2026 · 5 min read

A down payment does exactly two things. It shrinks the number the interest rate is applied to, and it moves the date on which the car stops being worth less than you owe on it. Everything else people say about down payments is a consequence of one of those two.

So let's take a single car, price it out the door, and branch it. The figures are computed from full amortization schedules and add up to the cent. The rate is illustrative, and so is the depreciation assumption — both are stated plainly below so you can swap in your own.

Vehicle on the windshield $17,200.00, New Jersey sales tax at 6.625% $1,139.50, title, registration and documentary fee $260.50 — out the door $18,600.00.
Illustrative APR 9.50% over 60 months. Not a quote, not an offer, not anybody's rate sheet.
For the equity line only: assume the car loses 18% of its value every year, smoothly. That is an assumption made to draw the line, not a forecast about this or any car.

Branch one

Financed $18,600.00

Monthly payment$390.63 Sixty of them, the last one $390.91.
Total interest$4,838.08 26.0% of the amount financed, paid for the privilege of keeping the cash.
Upside down untilMonth 30 At month 12 the balance is $15,548.85 against an assumed value of $14,104.00 — a gap of $1,444.85.
Total cash out$23,438.08

Branch two

$2,000

Financed $16,600.00

Monthly payment$348.63 $42.00 a month less than branch one.
Total interest$4,317.90 $520.18 less than branch one.
Upside down untilNever At month 12 the balance is $13,876.89 against $14,104.00 — $227.11 to the good, and widening from there.
Total cash out$22,917.90

Branch three

$4,500

Financed $14,100.00

Monthly payment$296.13 $94.50 a month less than branch one.
Total interest$3,667.50 $1,170.58 less than branch one.
Upside down untilNever At month 12 the balance is $11,786.95 against $14,104.00 — $2,317.05 of equity.
Total cash out$22,267.50

What the three columns actually say

Read the bottom row across. $23,438.08, $22,917.90, $22,267.50. Putting $4,500 down instead of nothing leaves you $1,170.58 better off over five years — and that figure is not a coincidence. It is exactly the interest saved, to the cent. A down payment does not buy you anything. It only stops you renting money you didn't need to rent.

That is a useful thing to know, because it sets a ceiling on how much this decision can possibly be worth. Nobody's down payment is going to save them the price of a second car. On a deal this size, at this illustrative rate, the whole spread between "nothing down" and "a quarter down" is about eleven hundred dollars.

The month that matters more than the money

The third row is the one people underestimate. In branch one the loan is larger than the car is worth for thirty months — two and a half years in which selling the car, trading it, or having it stolen or wrecked leaves you writing a check to close out a loan on a car you no longer have. In branches two and three, under the same assumption, that never happens.

That is the real function of a down payment, and it is a risk function rather than a savings function. It is also why the gap is worth drawing rather than describing, and why gap coverage is a serious question in branch one and close to an irrelevance in branch three.

The case for putting less down

Now the part that most articles on this subject leave out.

A down payment converts liquid money into equity in a depreciating asset. Money in your account can pay for a transmission, a layoff, or a $1,600 emergency. Money inside a car can only be retrieved by selling the car, which takes weeks and costs you the car. If emptying your savings to get to $4,500 leaves you with nothing behind it, branch three is not the safe choice — it only looks like the safe choice.

The comparison that decides it is narrower than it sounds. The extra $4,500 bought $1,170.58 of avoided interest over five years. If that same $4,500 is the only thing standing between you and financing a repair on a credit card at a far worse rate, it has done more good in your account than in the car. Run that against your own numbers, not ours.

Three ways the question gets asked badly

"What do I need to put down?"

This invites an answer about approval rather than arithmetic, and we can't give you that answer honestly — what any lender requires is between you and that lender, it varies, and we won't guess. Ask instead: what does each dollar down change about the payment and the total?

"Can you get the payment to $350?"

Almost always yes, and there are three levers — more down, a longer term, or a cheaper car — that produce wildly different five-year outcomes while hitting the same monthly number. If the lever isn't named, assume it was the term. That is the whole problem with budget-first conversations.

"Should I put my trade toward it?"

A trade-in is a down payment that arrives on wheels, and it should be priced as its own transaction before it is applied to this one. Agree what the car you're buying costs. Then agree what the car you're leaving is worth. Two numbers, settled separately, in that order.

Our version of the answer. Enough that you are not upside down for long, and never so much that you have no cash behind you. On a car in this price range that usually lands somewhere between branch two and branch three — and if you want, we'll run your own numbers on paper before anything is signed, including the version where you put nothing down.

Every figure on this page was computed from a full 60-month amortization schedule at the stated illustrative rate and verified to the cent; the final payment in each branch differs from the other 59 by a few cents, as it does on a real contract. The 18%-a-year depreciation used for the equity line is an assumption chosen to make the comparison legible, not a prediction about any vehicle. Rates shown are illustrative and are not offers of credit. Nothing on this page is financial advice.