A car loan calculator that turns the real numbers from a dealer quote — vehicle price, cash deposit, trade-in, APR, term, fees and sales tax — into the figure that actually matters: your monthly payment. It also shows the amount financed, the total interest you will pay, the total cost of the car, and a full month-by-month amortisation schedule so you can see exactly how each payment splits between interest and principal. It is built for anyone comparing finance offers, deciding how big a deposit to put down, weighing a longer term against the extra interest it costs, or checking whether a balloon (PCP-style) deal is worth it.
How it works
Car finance is a standard amortising loan. First the tool works out the amount financed: it takes the vehicle price, adds sales tax or VAT and any fees you choose to roll in, then subtracts your cash deposit and your net trade-in — the trade-in value less any finance still owed on that old car. If you owe more than the trade-in is worth, that negative equity is added back onto the new loan and the calculator flags it.
It then applies the amortising-loan formula to that balance using the monthly rate (your APR divided by 12) over the number of months you set. Crucially, it does not just print a formula result — it simulates every single month, charging interest on the outstanding balance and applying the payment to clear principal, rolling the balance forward until it hits zero. That keeps rounding honest and lets it show you a true schedule. If you enter a balloon / GMFV payment, the present value of that lump sum is removed from the financed amount before the monthly payment is calculated, then settled in the final month.
Worked example
Suppose a car is priced at 25,000, you put down a 3,000 deposit, the APR is 7.9% and the term is 60 months (5 years), with no trade-in, fees or tax.
- Amount financed: 22,000
- Monthly payment: about 445
- Total interest over the 5 years: roughly 4,700
- Total cost of the car: about 29,700
Now stretch the same loan to 72 months: the monthly payment drops to about 385, but the total interest climbs to roughly 5,700 — you pay around 1,000 more for the lower monthly figure. Add a 2,000 trade-in instead and the amount financed falls to 20,000, cutting both the monthly payment and the interest. The schedule below the result makes the trade-off visible at a glance.
Formula note: monthly payment M = P · r(1+r)ⁿ ⁄ ((1+r)ⁿ − 1), where P is the amount financed, r is the monthly rate (APR ÷ 12 ÷ 100) and n is the term in months. With a balloon B, P is first reduced by B ⁄ (1+r)ⁿ. When the APR is 0, the payment is simply (P − B) ⁄ n.
Every figure is calculated in your browser — no numbers are uploaded or stored.