Auto Loan Calculator

How it works

Looking beyond the vehicle's monthly payment

Compare the vehicle price, down payment, trade-in treatment, fees, and financing term together. A longer term can lower the monthly payment while increasing total interest. The payment-budget mode works backward from an installment you choose. For tax comparisons, select the applicable supported state treatment and review its notes; a vehicle's advertised price alone does not capture the financed amount.

Monthly payment: formula and assumptions

Financed amount = price − down − trade + trade debt − rebate + tax + financed fees.

Sales-tax treatment varies by jurisdiction. Select the trade-in tax treatment and enter your applicable tax rate.

Payment budget & vehicle price: formula and assumptions

Financed principal = price − down − trade + trade debt − rebate + financed tax and fees.

The reverse calculation solves for a price consistent with the budget and entered tax policy. Percentage down payment is solved together with the price. Local tax treatment must be entered explicitly.

US state tax treatment and offer comparison: formula and assumptions

Taxable base = max(0, price + taxable fees − eligible trade deduction − eligible rebate); financing includes price, payoff, credits and financed costs.

Current scoped dealer-purchase rules for all 50 states and DC are available as source notes. A subset supports automatic base treatment; special or unresolved cases use an actual quoted tax amount. State choice does not determine a local rate.

Worked example

Reference example currency: USD. These fixed examples do not change with your calculator preferences.

Using the Monthly payment example:

Vehicle price ($)

35000

Cash down payment ($)

5000

Trade-in value ($)

0

Amount owed on trade-in ($)

0

Cash rebate ($)

0

Sales tax rate (%)

6

Trade-in reduces taxable price

Yes

Financed fees ($)

500

Annual interest rate (%)

6.5

Loan term (years)

5

Financed amount = price − down − trade + trade debt − rebate + tax + financed fees.

Example result

These are illustrative inputs. Change the values to explore a different scenario.

What to keep in mind

Calculate a payment, a vehicle-price budget, or rebate-versus-rate offers using the entered price, down payment, gross trade allowance, trade debt, taxes and fees.

The state-tax mode includes scoped 2026 guidance for all 50 states and DC. Automatic taxable-base presets are available only where the listed dealer-purchase conditions are satisfied; other cases use a verified base or quoted tax amount.

State selection does not determine a local rate. Confirm transaction eligibility, taxable fees, rebate treatment and trade allowance using the selected state’s primary sources.

Tax, fees and trade debt are counted once in the selected cash/financed treatment. Private sales, exemptions, special vehicle classes and other transactions outside the preset need separately verified tax treatment.

Formula references

• CFPB: understanding mortgages (opens in a new tab)
• Investor.gov: financial tools and calculators (opens in a new tab)
• CFPB: comparing auto loans (opens in a new tab)

References explain the underlying methods; they do not imply endorsement or individual professional review of Finflo.

Common questions