Estimate your monthly payment and total cost — loan or lease — with California's sales tax handled correctly (including the trade-in rule most calculators get wrong).
Estimate only. Confirm tax with CDTFA address lookup, fees with California DMV, and your rate with the lender. CA RTC § 6012 controls the no-trade-in-deduction rule.
Buying or leasing a car in California has one specific quirk that affects almost every transaction: California does not give you a sales-tax break on your trade-in. That single rule changes the math, and most national calculators ignore it.
In most states, your sales tax is calculated on the price after your trade-in credit. In California, sales tax is calculated on the full negotiated price before the trade-in, and the trade-in is applied as a post-tax credit that reduces what you finance. On a $42,900 vehicle with an $8,200 trade-in:
| Step | Most states | California |
|---|---|---|
| Taxable amount | $42,900 − $8,200 = $34,700 | $42,900 (full price) |
| Sales tax @ 9.5% | $3,296.50 | $4,075.50 |
| Tax difference | — | +$779 more in California |
The calculator's trade-in field reduces only the financed amount, not the taxable amount — which is what actually happens on a California sales contract.
A dealer discount that lowers the negotiated price reduces both the taxable amount and the tax. A manufacturer rebate or incentive does not — California applies it after tax, like a trade-in. Read your contract line by line: shifting a $1,000 dealer-funded discount to a manufacturer rebate costs you about $100 in tax at California's typical rate.
Every lease payment has three pieces:
California is one of the states that taxes each monthly lease payment rather than the full capitalized cost upfront, which keeps your at-signing cost lower and spreads the tax across the lease. The money factor is the lease equivalent of an interest rate — multiply it by 2,400 for an approximate APR.
The U.S. average 60-month new-car loan in mid-2026 is around 6.97% (Bankrate). California credit unions consistently price below that, with members commonly seeing 4.2%–5.5% APR on new cars and 5.5%–8% on used. The best leverage is pre-approval from a credit union before you walk into the dealer — it caps the rate the dealer can mark up.
| FICO Score | Typical New Auto APR (CA, 2026) | Typical Used Auto APR |
|---|---|---|
| 720+ | 4.2% – 5.5% | 5.5% – 7.5% |
| 660 – 719 | 5.5% – 7.5% | 7.5% – 10.0% |
| 620 – 659 | 7.5% – 11.0% | 10.0% – 14.0% |
| Below 620 | 11.0%+ | 14.0%+ |
Itemize these with the Vehicle Registration / DMV calculator.