You found a car you want, you live in the St. Louis area, and you need to know what the tax bill will be before you bid. Missouri does not charge one flat rate. You pay the state rate plus the local rate for your home address, and in St. Louis that local piece changes a lot from one town to the next.
The short answer: Missouri charges 4.225% state sales tax on a car, plus the local sales tax where you live, on the price minus any trade-in. In the St. Louis area that totals 9.679% in St. Louis City, 7.738% in unincorporated St. Louis County, and 5.95% in unincorporated St. Charles County. You pay it at the license office within 30 days of purchase.
Updated October 6, 2026. Checked against the Missouri Department of Revenue motor vehicle sales tax rate chart, the DOR October to December 2026 sales tax rate table, RSMo 144.025, and the Illinois Department of Revenue. Sources are linked at the bottom.
Key takeaways
- Two parts: 4.225% state tax plus the local rate for the address on your title application.
- St. Louis range: from 5.95% in unincorporated St. Charles County to 9.738% in Kirkwood, based on the DOR chart.
- Taxed amount: the purchase price minus any trade-in allowance or rebate.
- Selling your old car: if you sell it yourself within 180 days before or after buying, that sale price can also come off the taxable amount.
- Deadline: title and pay within 30 days, or pay a $25 penalty that grows by $25 every 30 days, up to $200.
How much is car sales tax in St. Louis?
Your rate depends on where you live, not where the car was sold. The Missouri Department of Revenue says the local tax applies “if the address of the applicant is within a city or county” on its chart. If you live inside city limits, the city rate applies. If you live outside any city, the county rate applies.
| Where you live | Local rate | Total with 4.225% state | Tax on $4,000 | Tax on $9,000 |
|---|---|---|---|---|
| St. Louis City | 5.454% | 9.679% | $387.16 | $871.11 |
| Unincorporated St. Louis County | 3.513% | 7.738% | $309.52 | $696.42 |
| Chesterfield | 4.513% | 8.738% | $349.52 | $786.42 |
| Florissant | 4.763% | 8.988% | $359.52 | $808.92 |
| Kirkwood | 5.513% | 9.738% | $389.52 | $876.42 |
| Unincorporated St. Charles County | 1.725% | 5.950% | $238.00 | $535.50 |
| St. Charles, O’Fallon, St. Peters | 3.725% | 7.950% | $318.00 | $715.50 |
| Wentzville | 4.225% | 8.450% | $338.00 | $760.50 |
Check your exact address. Some cities have more than one site code on the chart because of special districts, and several smaller St. Louis County cities show new rates on the October 2026 state table. Run your address in the DOR motor vehicle sales tax calculator before you bid.
How do you calculate Missouri car sales tax?
The math is simple once you know your local rate.
- 1. Start with the purchase price on your bill of sale or invoice.
- 2. Subtract any trade-in allowance or rebate shown on your paperwork.
- 3. Add 4.225% to your local rate from the table above or the DOR calculator.
- 4. Multiply the taxable amount by that total rate.
Example 1: a $4,000 car, St. Louis City buyer
$4,000 x 9.679% = $387.16 in sales tax. Add the $8.50 title fee and $9 processing fee and you pay $404.66 at the license office, before plates.
Example 2: a $9,000 car with a $2,000 trade-in, unincorporated St. Louis County
$9,000 minus $2,000 = $7,000 taxable. $7,000 x 7.738% = $541.66. Without the trade-in, the same car would cost $696.42 in tax, so the trade saves you $154.76.
Tax is only one line. Before you bid, add up the whole cost, which we walk through in mistakes that make buyers overpay at car auctions.
Does a trade-in or selling your old car lower the tax?
Yes, both can. Under RSMo 144.025:
- Trade-in: tax is figured only on the price above the trade-in allowance. If the trade-in plus any rebate is more than the price, no sales tax is owed.
- Selling it yourself: the same credit applies if you sell your old vehicle and buy the next one within 180 days before or after that sale. Bring the bill of sale showing the price to the license office.
- Rebates: a seller or manufacturer rebate comes off the taxable price if your paperwork shows it.
The 180-day rule matters for auction buyers. You usually cannot trade a car in at an auction, but you can sell your old car privately and still get the credit if the timing lines up.
Do you pay sales tax on a private sale, a gift, or an auction car?
- Private sale: yes. The DOR collects the tax when you apply for title, no matter who sold you the car.
- Auction car: yes, the same way. You pay Missouri state and local tax on the purchase price when you title it.
- Gift: the DOR has a separate process. The giver writes “GIFT” in the sale price area of the title (not $1) and you bring a General Affidavit (Form 768) or a written gift statement. Our guide to gifting a car in Missouri walks through every step.
For every form you will need at the license office, read our guide to Missouri title transfer. If the title and registration steps still blur together, car registration vs title transfer explains the difference.
When and where do you pay car sales tax in Missouri?
You pay at a Missouri license office when you title the car. According to the DOR Buying a Vehicle page:
| Item | What Missouri says |
|---|---|
| Deadline | 30 days from the purchase date to title and pay sales tax |
| Late penalty | $25 on day 31, plus $25 for every 30 days after, up to $200 |
| Title fee | $8.50, plus a $9 processing fee |
| Sales tax | 4.225% state plus local, on the price minus any trade-in |
A change is coming for dealer purchases. A 2023 law, SB 398, requires Missouri licensed dealers to collect and remit sales tax once the state’s new motor vehicle system is in place. As of today, the DOR still tells buyers to pay when they title. Private sales and out-of-state purchases are still paid at the license office. Bought the car in another state? See how the tax credit works in our guide to registering an out-of-state car in Missouri.
Most St. Louis-area buyers also need an emissions test at title transfer. See St. Louis emissions testing for who needs one and what it costs. Our St. Louis car auctions guide covers the test, the cost, and who is exempt.
Live in the Illinois Metro East?
Illinois runs its own vehicle tax. According to the Illinois Department of Revenue, you file Form RUT-25 for a car bought from an out-of-state dealer or auction, or Form RUT-50 for a private-party purchase. Both are due within 30 days, and the payment goes to the Illinois Department of Revenue, separate from Secretary of State title fees. See car auctions in Illinois for more.
How to keep the tax bill low
- Buy for less: tax is a percent of the price, so a lower price means less tax. Our guide to cars under $1,000 in St. Louis shows what a small budget can buy.
- Time your sale: sell your old car within 180 days of buying to use the credit.
- Title on time: the late penalty is pure waste. Count 30 days from the purchase date on your paperwork.
- Budget it up front: add tax to your maximum bid before the auction, not after. Our guide to buying at auction and transferring the title walks through the full process.
Why St. Louis buyers bid on Remarket Space
Remarket Space is an online car marketplace open to the public. You do not need a dealer license or a membership. Every listing has an inspection report, a free Carfax, real photos, an HD virtual test drive, and the out-the-door total with a delivery quote, so you can add Missouri tax to a number you already trust. Out-of-state buyers do not pay Minnesota DMV fees at checkout, and you pay your Missouri tax at home when you title the car. The fee tiers are on our pricing and fees page.
See cars up for auction now, learn how bidding works, or browse cars under $5,000, cars under $10,000, and used sedans. Those pages list cars currently in Minnesota, and each one ships to St. Louis with a delivery quote. New to bidding? Read how to buy a vehicle on Remarket Space or our guide to car auctions in Missouri.
Frequently asked questions
Missouri charges 4.225% state sales tax on a vehicle, plus the local sales tax for the address where you live. Tax applies to the purchase price minus any trade-in allowance or rebate, and you pay it when you title the car at a Missouri license office.
In unincorporated St. Louis County the total is 7.738%, which is 4.225% state plus 3.513% local. Cities inside the county add more. For example, Chesterfield totals 8.738%, Florissant 8.988%, and Kirkwood 9.738% on the Department of Revenue chart.
St. Louis City buyers pay 9.679% in total: 4.225% state tax plus 5.454% local tax. On a $4,000 car that is $387.16, and on a $9,000 car it is $871.11, before the $8.50 title fee and $9 processing fee.
Yes. Missouri collects state and local sales tax when you apply for title, no matter if you bought from a dealer, an auction, or a private seller. You have 30 days from the purchase date to title the car and pay the tax.
Yes. Tax is figured only on the price above the trade-in allowance. If you sell your old vehicle yourself within 180 days before or after buying the new one, that sale price can also reduce the taxable amount if you bring the bill of sale.
Missouri charges a $25 title penalty on the 31st day after purchase. It grows by another $25 for every 30 days you are late, up to a maximum of $200, on top of the sales tax you still owe.
Illinois residents report vehicle tax to the Illinois Department of Revenue. Use Form RUT-25 for a car bought from an out-of-state dealer or auction, or Form RUT-50 for a private-party purchase. Both are due within 30 days.
Sources
- Missouri Department of Revenue: Motor Vehicle Sales Tax Rate Chart
- Missouri Department of Revenue: Sales and Use Tax Rate Tables, October to December 2026
- Missouri Department of Revenue: Motor vehicle sales tax calculator
- Missouri Department of Revenue: Motor vehicle titling and registration
- Missouri Department of Revenue: Buying a vehicle
- Missouri Department of Revenue: Selling and gifting a vehicle
- Revised Statutes of Missouri 144.025: Trade-ins, rebates, and the 180-day rule
- Missouri Department of Revenue: 2023 law changes, including SB 398 dealer tax collection
- Illinois Department of Revenue: Tax requirements for vehicles
This guide is general information, not legal or tax advice. Rates change by quarter, so confirm your rate with the Missouri Department of Revenue before you buy.
