DEALPROOF TOOLKIT

Check every part of the deal.

Use the dealer's real numbers to expose the complete price, loan cost, trade position, taxes, and fees before you sign.

No signup.Every calculator uses the same private, on-device DealProof system.

FREE BUYER TOOLS

Choose what you need to check

Combine price, taxes, fees, trade equity, cash down, APR, and term.

Build the full deal → STATE TAX

Estimate vehicle tax and see how an eligible trade-in changes the taxable price.

Check my state → PAYMENT

Estimate the payment, amount financed, total interest, and full loan cost.

Calculate a payment → COMPARE

Put two APR and term combinations side by side using the same principal.

Compare two loans → PAY OFF

See how extra principal could reduce the payoff time and interest.

Test an extra payment → TRADE

See how old debt changes the next loan and its lifetime cost.

Check my trade → FEES

Translate doc fees and add-ons into payment and financed cost.

Review the fees → BUDGET

Work backward from a payment ceiling to a realistic vehicle price.

ONE CLEAR PROCESS

Choose a price and payment limit before shopping so the target cannot drift.

Enter every buyer's-order figure and separate the vehicle price from the extras.

Run the dealer offer against another lender using the exact same amount financed.