Estimate sales or use tax on a vehicle purchase in Montana.
Car purchase tax in Montana: the tax applies to the price minus trade-in (where allowed) at the state/local car-sales-tax rate you enter, typically 3–8% plus local additions.
Tax
Tax = (price − trade-in) × rate + fees
Estimate — exact rules vary by state and locality.
Many states allow subtracting the trade-in, but rules vary.
Rates are approximate reference values. Local rates, exemptions and rules can differ, so treat the output as a planning figure only.