Car Payment Calculator: Auto Loan Payment With Tax, Trade-In and Fees
Most car payment calculators start with a loan amount you have not actually worked out yet. This Car Payment Calculator starts one step earlier, with the deal itself: vehicle price, down payment, trade-in value, sales tax, and fees. It builds the true amount financed first, tax charged on the price after the trade-in comes off, fees rolled in, and only then works out the monthly payment. On the pre-filled example, a $35,000 vehicle turns into $28,515.00 financed and a payment of $549.82 a month, with the total interest and the full out-the-door cost shown next to it.
Two ground rules before the numbers. First, this is an independent estimator that uses the standard amortization formula and works with an offer from any bank, credit union, or dealer; it is not affiliated with any lender, and it cannot quote you a rate. Enter the APR you are actually offered and the payment math will be exact. Second, this one page now covers both jobs that used to sit on two pages: the full deal build above, and the simpler case where you already know the price and your down payment and just want the payment. That simpler case is worked through in its own section below, with the same tool.
Estimate only. Your actual rate depends on credit history, term, vehicle age, and loan-to-value, and varies by lender. This tool works with an offer from any bank, credit union, or dealer, and is not affiliated with any lender.
Quick Answer
Key takeaways
- Your payment is based on the amount financed, not the sticker price. Tax and fees push it up; down payment and trade-in pull it down.
- A trade-in does double duty in most states: it reduces the loan and the taxable amount at the same time. A $4,000 trade-in at 6.5% saves $260.00 of tax on top of the $4,000.
- If you only know the price and your down payment, set trade-in, tax, and fees to zero: a $30,000 car with $5,000 down at 6.5% over 60 months is $489.15 a month and $4,349.22 of interest.
- Stretching the pre-filled loan from 36 to 84 months cuts the payment from $866.06 to $415.06 and raises total interest from $2,663.20 to $6,350.11. The term, not the payment, is where the real cost hides.
- Quick Answer
- How the amount financed is built, line by line
- Worked example: the $35,000 car, fully loaded with the boring parts
- Just the price and a down payment? The simple case, covered here
- What an extra $1,000 down actually buys you
- The term decides what the car really costs
- Your APR moves the same deal by thousands
- Zero down, honestly assessed
- Looking for BECU's own calculator or rates?
- What competing calculators miss
How the amount financed is built, line by line
The amount financed is the number your payment actually comes from, and it is assembled in a specific order. Get the order wrong and every downstream figure is wrong with it.
Start with the vehicle price. The negotiated price, $35,000 in the worked example, before anything is added or subtracted.
Subtract the down payment and the trade-in. $35,000 minus $5,000 cash minus $4,000 trade leaves $26,000 of price still to cover.
Add sales tax on the price after the trade-in. Taxable amount is $35,000 minus $4,000 = $31,000, and 6.5% of that is $2,015.00. The trade-in just saved $260.00 of tax as well as $4,000 of price.
Add any fees you roll into the loan. $500 of documentation, title, and registration fees brings the amount financed to $28,515.00.
Amortize. At 5.89% APR over 60 months, $28,515.00 costs $549.82 a month, $32,989.05 in total payments, and $4,474.05 of interest.
The tax step is where generic calculators quietly go wrong. Many apply tax to the full price, which overstates the loan in states that credit the trade-in against the taxable amount. Washington is one of those states: the Washington Department of Revenue explains that the selling price for sales tax excludes trade-in property of like kind, so a vehicle traded for a vehicle comes off before tax is figured. The Consumer Financial Protection Bureau makes the same total-cost point in its guidance on what you can negotiate when shopping for a car or auto loan: the APR, the term, and the amount you borrow decide the real cost, and all three are worth comparing across lenders before you reach the dealership.
Worked example: the $35,000 car, fully loaded with the boring parts
Every figure below is the pre-filled calculator's exact output. Change any input and the whole column moves, which is the point of building the deal instead of guessing a loan amount.
| Figure | Value |
|---|---|
| Vehicle price | $35,000.00 |
| Down payment and trade-in | $5,000.00 + $4,000.00 |
| Sales tax (6.5% of $31,000 after trade-in) | $2,015.00 |
| Fees rolled in | $500.00 |
| Amount financed | $28,515.00 |
| Monthly payment (5.89% APR, 60 months) | $549.82 |
| Total interest paid | $4,474.05 |
| Total of 60 payments | $32,989.05 |
| Out-the-door cost (down + trade + payments) | $41,989.05 |
There is a plain way to know the amortization itself is right. Credit unions and banks publish payment examples with their rate schedules, and any honest example has to reproduce under this formula. A widely published one is $20,000 borrowed for 5 years at 5.89% APR costing $385.63 a month. Run $20,000 at 5.89% over 60 months through the calculator above (price $20,000, everything else zero) and you get $385.63, to the cent. The formula is the industry standard; what varies between calculators is whether the amount fed into it includes tax and fees honestly. For a loan where you are paying extra principal each month to shorten the term, the auto loan principal payment calculator isolates that piece of the math.
Just the price and a down payment? The simple case, covered here
Plenty of buyers do not need the full deal build. If a dealer has already quoted you an out-the-door price, or you are comparing two loan offers on a car you have already priced, the only inputs that matter are price, down payment, APR, and term. This calculator handles that case too: leave the trade-in at zero (or add your trade-in value into the down payment field's total in your head and enter the combined cash-plus-trade figure as the down payment), set sales tax to 0 and fees to 0, and the amount financed is simply price minus down payment.
Worked through with the same tool: a $30,000 car with $5,000 down at 6.5% APR over 60 months finances $25,000.00 and costs $489.15 a month, with $4,349.22 in total interest and $29,349.22 in total payments. Those are this calculator's exact outputs on those inputs, not a second tool's numbers, because the underlying math is identical: one amortization formula, with the deal-building fields switched off.
| Simple case: $30,000 price, $5,000 down, 6.5% APR | 60 months | 72 months |
|---|---|---|
| Amount financed | $25,000.00 | $25,000.00 |
| Monthly payment | $489.15 | $420.25 |
| Total interest | $4,349.22 | $5,257.87 |
| Total of payments | $29,349.22 | $30,257.87 |
The 72-month column is the lesson this simpler case teaches best. The payment falls by $68.90 a month, which feels like relief at the dealership, and the interest bill rises by $908.65 while you stay in debt a year longer. Dealers present the monthly number because it is the one that sells cars; the total interest column is the one that should decide the term. Before stretching a term to make a payment fit, check whether the payment still sits comfortably inside your overall debt load with a debt-to-income ratio calculator.
What an extra $1,000 down actually buys you
A down payment is the most underrated lever in the whole deal, because every dollar of it is a dollar you never pay interest on. On the simple case above, raising the down payment from $5,000 to $6,000 cuts the amount financed to $24,000.00, drops the payment from $489.15 to $469.59, and saves $173.97 of interest over the 60 months. That works out to about $19.57 a month per extra $1,000 down at 6.5% over 60 months.
The second effect does not show in the calculator but matters at the lender: a bigger down payment lowers your loan-to-value, the share of the car's value you are borrowing. Lower loan-to-value is one of the factors lenders price on, alongside credit history, term, and vehicle age, so the same $1,000 can also move you into a better rate tier. It also starts you with an equity cushion, which is the difference between selling a car you owe $18,000 on for $19,000 and owing $21,000 on a car worth $19,000.
The term decides what the car really costs
Same car, same amount financed ($28,515.00), same 5.89% APR. Only the term changes, and with it the entire character of the loan. The bars below are total interest, the purest measure of what borrowing costs you.
| Term | Monthly payment | Total interest | Total of payments |
|---|---|---|---|
| 24 months | $1,262.39 | $1,782.34 | $30,297.34 |
| 36 months | $866.06 | $2,663.20 | $31,178.20 |
| 48 months | $668.24 | $3,560.45 | $32,075.45 |
| 60 months | $549.82 | $4,474.05 | $32,989.05 |
| 72 months | $471.10 | $5,403.96 | $33,918.96 |
| 84 months | $415.06 | $6,350.11 | $34,865.11 |
The 84-month loan saves $134.76 a month against the 60-month loan and charges $1,876.06 more interest for the privilege, while keeping you in debt two years longer on a depreciating asset. The CFPB warns about exactly this trade in its auto loan materials: a longer term lowers the payment while raising the total cost and the risk of owing more than the car is worth. Long terms are also where the market has been heading: according to Experian's State of the Automotive Finance Market data, the average new-car loan in mid-2026 ran about 69.5 months, which is worth knowing before a dealer presents 72 or 84 months as the normal choice. The average loan tenure calculator puts typical term lengths in context, and once you have signed, the debt free date calculator turns the term into the calendar date the payments actually end.
Your APR moves the same deal by thousands
Hold the deal fixed at $28,515.00 financed over 60 months and change only the rate. A two-point better APR is worth more than most of the options buyers haggle over at the dealership.
| APR (same $28,515.00, 60 months) | Monthly payment | Total interest |
|---|---|---|
| 5.89% (pre-filled example) | $549.82 | $4,474.05 |
| 7.89% | $576.68 | $6,085.88 |
| 10.00% | $605.86 | $7,836.57 |
Moving from 10% to 5.89% on this one loan saves $56.04 a month and $3,362.52 of interest, without changing the car, the term, or the down payment by a cent. That is why the rate deserves the shopping effort: Experian's market data put the average new-car rate at 6.35% and the average used-car rate at 11.19% in the second quarter of 2026, and the spread inside each average, by credit tier, is several points wide. The CFPB explains in its explainer on what APR is why the APR, which folds lender fees into the rate, is the right figure for comparing offers rather than the bare interest rate. Get two or three pre-approvals, enter each APR here, and compare the total interest column, not the monthly payment the dealer quotes you.
Zero down, honestly assessed
The calculator accepts a $0 down payment because qualified buyers do finance the full price. On a $30,000 vehicle with no trade, tax, or fees at 5.89% over 60 months, that is $578.45 a month, $4,707.05 of interest, and $34,707.05 in total payments. Whether it is wise depends on your reserves and the car's depreciation curve, not on the payment alone.
When zero down can make sense
- You keep a real emergency fund instead of draining it into a depreciating asset.
- Your APR is low enough that the extra interest is modest, as in the example above.
- You plan to keep the car well past the loan term, so early negative equity never gets tested by a sale.
When it usually does not
- The car drops in value faster than the balance falls, leaving you owing more than it is worth.
- A longer term is stacked on top of zero down, compounding both the interest and the equity gap.
- The monthly payment only fits because the term was stretched, the exact pattern the CFPB shopping sheet is built to catch.
The CFPB's auto loan shopping sheet exists for this moment: write each offer's price, taxes, fees, down payment, trade-in, rate, and term in one place and compare totals, not payments. This calculator is built to fill in that sheet for any lender's deal, line by line.
Looking for BECU's own calculator or rates?
This page used to carry a credit union's name, so some readers will land here looking for that lender specifically. To be plain about it: this calculator is not BECU's, and Calculator Zilo is not affiliated with, endorsed by, or sponsored by BECU (Boeing Employees Credit Union). It is an independent estimator that runs the same standard amortization every lender uses, which is why it works for a BECU offer, a bank offer, or a dealer offer equally well.
If you want BECU itself, use BECU's own site: its official auto loans page covers its current offers and application process, its own auto loan payment calculator is there too, and its published Consumer Lending Rates disclosure (form P-463) is the document to trust for its current rate ranges, since schedules are revised several times a year. One useful cross-check from that disclosure: BECU illustrates its new-auto rates with a payment example of $385.63 a month on $20,000 over 5 years at 5.89% APR, and this calculator reproduces that figure exactly on the same inputs, so a number you work out here will line up with the lender's own math when you apply.
What competing calculators miss
The big lender and marketplace calculators are polished, and most of them share the same two limits. The first is that they start from a loan amount, or bury the tax and fee fields behind an advanced panel, so the amount financed is wrong on any deal with a trade-in, which is most deals. The second is presentation: the monthly payment gets the headline and the total interest gets the small print, which is the dealer's framing, not the buyer's.
At the other end, the third-party pages built around a single lender's name often state rate figures that conflict with that lender's current published schedule, sometimes within the same article, because nobody re-checked the disclosure document. This page takes the narrower, checkable position: the deal is built in the right order, the trade-in tax credit is applied and its state-by-state limit is stated, total interest and out-the-door cost sit next to the payment on every result, and no lender's rates are quoted as current when a dated schedule is the only honest version. Where a lender's own published example exists, the math here is checked against it.
Frequently asked questions
No. It is an independent estimator that uses the standard auto loan amortization formula and works with an offer from any bank, credit union, or dealer. It is not affiliated with any lender. If you arrived here looking for BECU specifically, BECU's official auto loans page and its current rate schedule (form P-463) are linked in the section above.
First build the amount financed: vehicle price, minus down payment, minus trade-in, plus sales tax on the price after the trade-in, plus any fees rolled in. Then amortize it: payment = P x r x (1 + r)^n / ((1 + r)^n minus 1), where P is the amount financed, r is APR / 100 / 12, and n is the term in months. On the worked example, $28,515.00 at 5.89% over 60 months gives $549.82 a month.
Yes. Set the trade-in to zero (or fold its value into your down payment figure), set sales tax to 0 and fees to 0, and the amount financed is simply price minus down payment. A $30,000 car with $5,000 down at 6.5% APR over 60 months finances $25,000.00 and costs $489.15 a month, with $4,349.22 of total interest.
Because in Washington and most states that allow a trade-in credit, you are taxed on the difference between the new vehicle's price and the trade-in's value, not on the full price. A $4,000 trade-in at a 6.5% rate saves $260.00 of tax on top of the $4,000 price reduction. A few states tax the full price with no trade-in credit, so check your state's rule and set the tax rate accordingly.
Usually it costs more than it helps. On a $25,000 loan at 6.5%, 72 months drops the payment from $489.15 to $420.25, a saving of $68.90 a month, but raises total interest from $4,349.22 to $5,257.87, an extra $908.65, and keeps you in debt a year longer. Take the shortest term whose payment genuinely fits your budget.
Directly, dollar for dollar on the amount financed. On a $30,000 car at 6.5% over 60 months, raising the down payment from $5,000 to $6,000 cuts the payment from $489.15 to $469.59, about $19.57 a month per extra $1,000 down, and saves $173.97 of interest. A larger down payment also lowers your loan-to-value, which can help you qualify for a better rate tier.
The APR on your actual offer or pre-approval, not an advertised floor. For context, Experian's market data put average rates at 6.35% for new cars and 11.19% for used cars in the second quarter of 2026, with wide spreads by credit tier. Run the calculator at your offered rate and at a point or two higher to see the true cost of a weaker rate before you negotiate.
Yes. A pre-approval from a bank or credit union gives you a rate for the dealer to beat and takes the dealer's financing markup out of the negotiation. Walk in with your payment and total interest already computed from this calculator, and negotiate the car's price and the rate, not the monthly payment.
At 0% APR there is no interest to spread, so the payment is simply the amount financed divided by the term. A $30,000 amount financed at 0% over 60 months is $500.00 a month exactly, and the total interest line reads $0. Promotional 0% offers usually require strong credit and a shorter term, so check what term the 0% rate actually covers.
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References
- Consumer Financial Protection Bureau, "Auto loans" consumer guide: the steps for getting an auto loan, from budgeting to closing, and comparing total cost across lenders. CFPB: Auto Loans. Accessed October 2026.
- Consumer Financial Protection Bureau, "What things can I negotiate when shopping for a car or auto loan?": APR, loan length, and amount borrowed as the negotiable levers that set total cost. CFPB: What Can I Negotiate When Shopping for an Auto Loan?. Accessed October 2026.
- Consumer Financial Protection Bureau, "Comparing Auto Loans" shopping sheet (Your Money, Your Goals): the worksheet format for recording price, tax, fees, down payment, trade-in, rate, and term per offer. CFPB: Comparing Auto Loans Shopping Sheet. Accessed October 2026.
- Consumer Financial Protection Bureau, "Know Before You Owe" auto loan worksheet: side-by-side comparison of total loan cost rather than monthly payment. CFPB: Auto Loan Worksheet. Accessed October 2026.
- Consumer Financial Protection Bureau, "What is APR?": why APR folds fees into the rate and is the right basis for comparing loan offers. CFPB: What Is APR?. Accessed October 2026.
- Consumer Financial Protection Bureau, "Servicemembers, arm yourself with basic car buying skills: how to shop for auto financing": term length, total cost, and down payment guidance for military buyers. CFPB: Servicemember Guide to Auto Financing. Accessed October 2026.
- BECU (Boeing Employees Credit Union), "Auto Loans and Car Loan Financing: New and Used": BECU's official auto loan offers and application process, the lender's own page for readers who came looking for BECU. BECU: Auto Loans. Accessed October 2026.
- BECU, "Auto Loan Calculator: Estimate Your Monthly Car Payment": BECU's own payment estimator, linked so readers can compare this independent tool with the lender's. BECU: Auto Loan Payment Calculator. Accessed October 2026.
- BECU, "Consumer Lending Rates and Related Disclosures," form P-463: BECU's published rate ranges and payment examples, including the $385.63 example on $20,000 over 5 years at 5.89% APR used as a math cross-check in this article. BECU: Consumer Lending Rates and Related Disclosures (P-463). Accessed October 2026.
- Washington State Department of Revenue, "Trade-ins": the selling price for retail sales tax excludes trade-in property of like kind, the rule behind this calculator's tax step. Washington DOR: Trade-ins. Accessed October 2026.
- Experian, "Average Car Payment in 2026" (State of the Automotive Finance Market, Q2 2026): average new-car payment $765, loan amount $43,610, rate 6.35%, term 69.5 months; used-car rate 11.19%. Experian: Average Car Payment. Accessed October 2026.
- Board of Governors of the Federal Reserve System, "Consumer Credit: G.19 Statistical Release": outstanding consumer credit and auto loan terms at commercial banks, background for typical term and rate conditions. Federal Reserve: Consumer Credit (G.19). Accessed October 2026.