How to Calculate Your Monthly Car Payment: Formulas, Taxes & Worked Examples
Master the federal TILA amortization formula, convert APR to monthly periodic interest, and verify any dealership payment quote by hand.
UNITED STATES AUTO LOAN & PAYMENT INTELLIGENCE PLATFORM
Auto Loan Calculator & Car Loan Calculator for Smart US Buyers
Use our institutional-grade auto loan calculator and car loan calculator to run an exact monthly car payment calculation before visiting a dealership. Accurately model your vehicle purchase price, down payment, annual percentage rate (APR), trade-in equity, state sales tax, dealer fees, total amount financed, and loan amortization across 36 to 84 months.
TILA Verified Actuarial Math
50 States Tax & Trade-In Rules
Instant Results • No Credit Pull
Q4 2026 US BENCHMARK DATA
LIVE USDNational Auto Finance Snapshot
New Car Prime APR
Prime 661–780
6.84%
Used Car Average APR
Pre-Owned Avg
11.83%
60-Mo Payment ($35K Car)
w/ $4K Down
$611/mo
60 vs. 72 Mo Savings
Interest Saved
+$1,854
Auto Loan Calculator
✓ US Truth-in-Lending (TILA) CompliantComprehensive US vehicle financing calculator with state sales tax, local sales tax, dealer doc fee, registration, and trade-in tax savings.
Estimated Monthly Car PaymentUSD • United States
$674.55/ month
Total Amount Financed$34,196.50
Total Interest Paid$6,276.50
Combined US Sales Tax$2,537.50
Total Out-of-Pocket Cost$44,473.00
Total Amount Financed (Principal)$34,196.50
Total Auto Loan Interest Paid$6,276.50
Down Payment & Trade-In Equity$4,000.00
US Truth in Lending Act (TILA) Disclosure: Calculations are estimates for planning purposes. Actual monthly car payment, annual percentage rate (APR), sales taxes, title/registration charges, and dealer documentation fees depend on your credit profile, lender terms, and US state/county registration rules.
COMPLETE AUTOMOTIVE CALCULATOR PLATFORM
Explore Our Dedicated Car Loans Calculator Suite
Select the specialized calculator built for your exact stage of the vehicle buying, financing, refinancing, or payoff journey. Every tool includes dedicated formulas, worked examples, and comparison tables.
FLAGSHIP TOOL
Main Auto Loan Calculator
Our comprehensive calculator for an auto loan and calculator for a car loan. Models vehicle purchase price, state & local sales taxes, 42-state trade-in tax credits, dealer doc fees, and annual/monthly amortization.
MOST POPULAR
Car Payment Calculator
Instantly calculate your car payment and estimate car payment amounts across 36, 48, 60, 72, and 84-month loan durations. Compare how APR and term length impact your monthly budget.
DEAL ANALYSIS
Financing a Car Calculator
Compare credit union pre-approvals vs. dealership financing, and evaluate 1.9% promotional APR offers against $2,500 customer cash rebates.
20/4/10 RULE
Car Affordability Calculator
Reverse-engineer your safe maximum vehicle purchase price from your annual household income, down payment, insurance, and fuel costs.
LOWER APR
Auto Loan Refinance Calculator
Replace a high-APR dealership loan with a lower credit union rate. Calculate monthly payment savings, total interest saved, and fee break-even months.
EARLY PAYOFF
Auto Loan Payoff Calculator
See how adding $50 to $200/month or a one-time tax refund lump sum toward principal cuts months off your loan duration and saves interest.
PRE-OWNED
Used Car Loan Calculator
Tailored for pre-owned vehicles with realistic used car APR tiers (7.05%–19.04%), vehicle age guidelines, and state sales tax calculations.
NEW INVENTORY
New Car Loan Calculator
Model brand-new vehicle financing with captive automaker promotional APRs (0.0%–4.9%), manufacturer rebates, and first-year equity protection.
LTV & EQUITY
Down Payment Calculator
Compare 0% down vs. 10% down vs. 20% down side-by-side to see how upfront cash lowers your loan-to-value (LTV) ratio and eliminates GAP insurance.
LEASE VS LOAN
Lease vs. Buy Calculator
Convert lease money factors to APR (MF × 2400), compare 36-month lease payments against buying, and calculate retained resale equity.
ACTUARIAL TRANSPARENCY & WORKED EXAMPLE
How Our Auto Loan Calculator Computes Your Exact Payment
Never treat a dealership finance quote as a black box. Below is the exact mathematical formula and a line-by-line worked example showing how US auto loans are structured.
STEP 1 • OUT-THE-DOOR PRINCIPAL (P)
Calculating the Total Amount Financed
Before interest is calculated, your lender determines your net loan principal (Total Amount Financed) by combining the vehicle price, taxable difference after trade-in, and fees:
P = (Price − TradeIn) × (1 + TaxRate) + TradeIn − DownPayment − NetTradeEquity + FeesSTEP 2 • TILA MONTHLY AMORTIZATION FORMULA (M)
Standard US Monthly Car Payment Equation
Every bank, credit union, and captive auto lender in the United States computes your fixed monthly payment (M) using this equation:
M = P × [ r(1 + r)n ] ÷ [ (1 + r)n − 1 ]
M
Monthly Car PaymentFixed principal + interest installment
P
Total Amount FinancedOut-the-door loan principal in USD
r
Monthly Periodic RateAnnual Percentage Rate (APR) ÷ 12
n
Loan Duration (Months)Total payments (36, 48, 60, 72, or 84)
REAL-WORLD WORKED EXAMPLE
60 MOS @ 6.84% APR$35,000 Vehicle Purchase Breakdown
1. Negotiated Vehicle Purchase Price
$35,000.00
2. Trade-In Vehicle Allowance (Tax-Deductible in 42 States)
− $5,000.00
3. Net Taxable Purchase Amount ($35,000 − $5,000)
$30,000.00
4. Combined State (6.0%) & Local (1.25%) Sales Tax (7.25%)
+ $2,175.00
5. Dealer Doc Fee ($399) + Registration ($185) + Title ($75)
+ $659.00
6. Cash Down Payment Paid at Signing
− $4,000.00
Total Amount Financed (Loan Principal P)
$28,834.00
Exact Monthly Payment
$568.78/mo
Total Interest Paid (60 Mo)
$5,292.80
Trade-In Sales Tax Saved
$362.50
EXPERIAN & FEDERAL RESERVE BENCHMARKS
Average US Auto Loan APRs by Credit Score & Loan Term
Your FICO Auto Score and chosen loan duration can swing your total vehicle cost by more than $10,000. Use these benchmark tables to audit any rate offered by a dealer.
Table 1: Average US Auto Loan Interest Rates (APR) by FICO Credit Tier
Representative monthly payments and total interest shown for a $35,000 loan over 60 months.
| US Credit Tier | FICO Auto Score | New Car Avg APR | Used Car Avg APR | Monthly Payment ($35K / 60 Mo New) | Total Interest Paid (New) |
|---|---|---|---|---|---|
| Super Prime | 781 – 850 | 5.38% | 7.05% | $666.52 / mo | $4,991.20 |
| Prime | 661 – 780 | 6.89% | 9.33% | $691.31 / mo | $6,478.60 |
| Nonprime | 601 – 660 | 9.83% | 14.12% | $740.91 / mo | $9,454.60 |
| Subprime | 501 – 600 | 13.18% | 19.04% | $799.49 / mo | $12,969.40 |
| Deep Subprime | 300 – 500 | 15.86% | 21.55% | $848.33 / mo | $15,899.80 |
Table 2: Car Loans Calculator Comparison by Loan Duration (36 vs. 48 vs. 60 vs. 72 vs. 84 Months)
Based on $30,000 total amount financed at 6.84% APR. See how stretching your loan term inflates total interest paid.
| Loan Duration | Monthly Car Payment | Total Interest Paid | Total Financed Cost | Equity & Financial Advisory Verdict |
|---|---|---|---|---|
| 36 Months (3 Years) | $924.14 / mo | $3,269.04 | $33,269.04 | Lowest Interest • Fastest Equity |
| 48 Months (4 Years) | $716.16 / mo | $4,375.68 | $34,375.68 | 20/4/10 Gold Standard |
| 60 Months (5 Years) | $591.79 / mo | $5,507.40 | $35,507.40 | Most Popular US Term |
| 72 Months (6 Years) | $509.16 / mo | $6,659.52 | $36,659.52 | High Underwater / LTV Risk |
| 84 Months (7 Years) | $450.45 / mo | $7,837.80 | $37,837.80 | Avoid • Costs $4,568 More Interest |
AUTOMOTIVE FINANCING RESEARCH & EDITORIAL LIBRARY
16 Expert Guides on Car Loans, Monthly Payments & Dealership Strategy
Written and verified by our US automotive finance analysts. Every guide includes worked math examples, state tax insights, and direct links to our interactive calculators.
Understanding Auto Loan Amortization: How Simple Daily Interest Is Calculated
Why early monthly car payments go mostly toward finance charges, how daily interest accrues, and how principal reduction accelerates over time.
Trade-In Equity, State Sales Tax Credits & Dealer Fees: Out-the-Door Guide
See which 42 US states deduct trade-in value before charging sales tax, how state doc fee caps work, and how to negotiate out-the-door pricing.
Car Affordability & Early Loan Payoff Strategies: The 20/4/10 Rule Explained
Protect your household cash flow with the 20% down, 4-year loan, 10% gross income framework—plus extra principal payoff shortcuts.
Average Auto Loan Interest Rates by Credit Score (2026 US FICO Tier Report)
Compare Super Prime, Prime, Nonprime, and Subprime auto loan APRs for new and used cars and learn how a 40-point FICO boost saves $2,400+.
60 vs. 72 vs. 84-Month Car Loans: The Hidden Cost of Long Auto Loan Terms
A side-by-side actuarial breakdown showing why 72- and 84-month car loans trap buyers in negative equity and double total interest costs.
0% APR Financing vs. Customer Cash Back Rebates: Which Saves You More?
When automakers offer 0%–1.9% APR OR a $2,500–$4,000 cash rebate, here is the exact break-even math to pick the winning option.
How and When to Refinance a Car Loan: Step-by-Step Guide to Lowering Your APR
Learn how soon after buying a car you can refinance, how to calculate title fee break-even months, and how to avoid term-extension pitfalls.
How Much Down Payment Do You Need for a Car? Comparing 0%, 10%, and 20% Down
See how your down payment percentage affects lender approval, loan-to-value (LTV) tiers, monthly payment size, and first-year depreciation.
How to Escape an Upside-Down Car Loan: Managing Negative Equity Smartly
Owe more on your trade-in than it’s worth? Learn why rolling negative equity into a new loan is dangerous and 4 proven ways to get above water.
Credit Union vs. Dealership Car Financing: How to Beat Dealer APR Markups
Understand how dealership finance reserve markups work and why walking in with a credit union pre-approval check gives you ultimate leverage.
Leasing vs. Buying a Car: Money Factor, Residual Value & Equity Compared
Learn how to convert lease money factors into APR, calculate acquisition and disposition fees, and compare 3-year lease costs against 5-year loan equity.
Used Car Financing Guide: How Vehicle Age, Mileage & LTV Affect Auto Loans
Discover lender age and mileage cutoffs (such as the 10-year / 100,000-mile rule), private-party vs. franchise dealer rates, and CPO financing perks.
Bi-Weekly Car Payments Explained: How 26 Half-Payments Cut Months Off Your Loan
Paying half your car payment every two weeks equals 13 full monthly payments a year—shaving 4 to 6 months and hundreds in interest off a 60-month loan.
When Is GAP Insurance Worth It? Calculating Loan-to-Value (LTV) & Total Loss Risk
Find out when Guaranteed Asset Protection (GAP) is essential, when a 20% down payment makes it unnecessary, and how to avoid $1,000 dealer GAP markups.
First-Time Car Buyer Financing Checklist: Pre-Approval to Out-the-Door Signing
A step-by-step US buyer playbook covering credit freezes, DTI ratios, co-signer rules, rate-shopping windows, and auditing the final Truth in Lending box.
FREQUENTLY ASKED QUESTIONS
Auto Loan Calculator & Car Payment Questions Answered
Direct, mathematically accurate answers to the most common questions about calculating car payments, APRs, sales taxes, and loan terms in the United States.
How do I calculate my monthly car payment using an auto loan calculator?
To calculate your car payment, enter the vehicle purchase price, down payment, trade-in value, state and local sales tax rate, dealer documentation fees, annual percentage rate (APR), and loan duration (36 to 84 months) into our auto loan calculator or car payment calculator. Our engine computes your net total amount financed and applies the federal Truth in Lending Act amortization formula to display your monthly payment, total interest paid, and payoff schedule.
What is the difference between APR and interest rate when financing a car?
The interest rate is the base annual percentage charged for borrowing the loan principal. The Annual Percentage Rate (APR) includes the base interest rate plus any mandatory prepaid finance charges, lender origination fees, and acquisition fees. Always compare offers using the APR on our financing a car calculator.
How does trading in a vehicle lower my state sales tax on a car loan?
In 42 US states, vehicle sales tax is assessed only on the net difference between the new car’s purchase price and your trade-in allowance. For example, trading a $15,000 car toward a $40,000 car in a 7% sales tax state reduces your taxable amount to $25,000—saving you $1,050 in sales tax and lowering your total amount financed.
How much car can I afford based on my annual salary?
Financial planners recommend the 20/4/10 rule: put at least 20% down, finance for no longer than 4 years (48 months), and keep your combined monthly car payment, auto insurance, and fuel under 10% of your gross monthly income. Run your exact salary on our car affordability calculator.
Is a 72-month or 84-month car loan a bad financial decision?
While 72- and 84-month loans reduce your monthly payment, they significantly increase your total interest paid and keep you underwater (owing more than the car is worth) for the first 3 to 4 years. If you must take a 60- or 72-month loan, use our auto loan payoff calculator to make extra monthly principal payments and pay it off early without penalty.
When does refinancing an existing auto loan make sense?
Refinancing makes financial sense when your credit score has improved, market APRs have dropped by at least 1.5% to 2.0%, or you originally accepted a marked-up dealership rate. Use our auto loan refinance calculator to verify your monthly savings and break-even timeline.