Car instalment with a deposit and an optional balloon payment.
Monthly instalment
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Balloon due at end
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Total cost
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Total interest
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What the dealership instalment actually contains
When a dealer quotes you a monthly figure for a car, several levers are buried inside it: the price, your deposit, the interest rate, the term, and often a balloon payment waiting at the end. This calculator unpacks them. You enter the vehicle price, your deposit, the annual interest rate, the term in months, and the balloon as a percentage of the price, and it returns the monthly instalment, the balloon due at the end, the total cost of the agreement, and the total interest you will pay. It turns a single headline number into something you can interrogate.
It is built for a car buyer comparing offers or testing how a bigger deposit or a balloon changes the monthly commitment. Vehicle finance in South Africa is one of the more expensive forms of secured borrowing once you add the interest over a long term, so seeing the full cost before signing is worth the two minutes.
How the instalment and balloon fit together
The calculator first subtracts your deposit from the price to get the financed amount. The balloon is set aside as a lump sum due at the end, so it is not amortised over the term in the usual way; instead the tool finances the present value of that future balloon and spreads the rest across your monthly payments. That is why a balloon lowers the monthly figure, you are simply not paying that slice off over the term. The interest rate is an annual figure converted to a monthly rate, and the instalment is the standard amortisation payment on the financed amount net of the balloon. The total interest is the whole cost of the agreement, deposit plus all instalments plus the balloon, minus the original price.
A R350,000 car with a deposit and a 10 percent balloon
Take a R350,000 vehicle, a R35,000 deposit, a 12.5 percent annual rate, a 60-month term, and a 10 percent balloon. The balloon is R35,000 and the financed amount is R315,000. The instalment works out to about R6,664 a month. Over the 60 months you pay roughly R399,840 in instalments, plus the R35,000 deposit and the R35,000 balloon at the end, for a total cost of about R469,840. Since the car cost R350,000, the interest is about R119,840. That balloon you still owe in full when the term ends.
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The balloon trap to watch
A balloon makes the monthly number look friendly, but it is borrowed comfort. At the end of the term you still owe the balloon, R35,000 in the example, and you must either pay it as a lump sum, refinance it, or sell the car to cover it. If the car is worth less than the balloon by then, which happens when depreciation outruns the plan, you are left covering the shortfall. A common mistake is choosing the biggest balloon to get the lowest instalment without a plan for the final lump sum. A practical tip is to size the balloon against what you realistically expect the car to be worth at term end, and to keep the term short enough that you are not still paying interest on a car well past its best years.
Who should run this before signing
Anyone comparing finance offers or tempted by a low advertised instalment. The tool lets you see the trade-offs plainly: a larger deposit cuts both the instalment and the total interest, while a bigger balloon cuts the instalment but leaves a debt at the end and usually raises the total interest. Run your own price and rate, then try nudging the deposit up and the balloon down to watch the total cost fall. Note this calculator covers the finance mathematics only; it does not include the on-the-road extras like an initiation fee, a monthly service fee, licensing, or compulsory insurance, so budget for those on top.
Will a bigger deposit or a bigger balloon save me more?
A bigger deposit genuinely saves you money, because it shrinks the amount you finance and therefore the interest you pay overall. A bigger balloon only shifts cost to the end; it lowers the monthly payment but typically increases the total interest and leaves you owing a lump sum. If your goal is the cheapest car overall, favour the deposit and keep the balloon small.
Does the quoted instalment include insurance and fees?
No. This calculation is the finance portion only. In practice your bank adds an initiation fee and a monthly service fee, and the lender will require comprehensive insurance, which can add a meaningful amount to the true monthly outlay. Always ask for the full instalment including fees and insurance before you compare offers.