Looking up sales tax on cars in Cook County Illinois? For a dealer purchase titled to a Cook County address on or after August 1, 2026, Illinois Auto Sales High-Rate is 8.75%. On a $30,000 price with no trade-in, sales tax is $2,625.00; add Illinois Secretary of State title $165 and passenger plates $151 for $316.00 in core SOS fees—$2,941.00 combined before any EV surcharge or private RUT-6 lines. Confirm the Auto Sales rate in MyTax for your purchase month.
How much is vehicle tax in Cook County?
Illinois does not put ordinary city general merchandise rates on titled cars. Dealers and many retailer paths use form ST-556 at the purchaser’s title/registration address Auto Sales High-Rate. For Cook County, that combined Auto Sales field is 8.75% effective 2026-08-01 (IDOR sales tax machine-readable files; NITA change explained in FY 2026-34). The state portion is 6.25%; the rest is local/NITA structure inside the Auto Sales field—not a separate guess.
Private-party tax uses the RUT-5 dollar chart for calendar year 2026—not 8.75%. Stack Cook County RUT-6 age brackets ($225 / $175 / $90) and, if your address is Chicago, Chicago municipal RUT-6 ($80 / $65 / $50 / $0). Exception path dollars can be lower ($25 Cook; Chicago $15 or $0 if age 15+).
Dealer — $30,000, no trade
Private-party path (not the dealer %)
Step-by-step formula
- Choose the path — Dealer/retailer ST-556 at Auto Sales 8.75%; private/gift/many transfers on RUT-50 with RUT-5 chart dollars.
- Dealer taxable base — Price minus qualifying trade-in, plus taxable documentary fees if charged. Financing interest does not change the tax.
- Multiply dealer base by 8.75% — Or look up RUT-5 dollars for private deals.
- Add SOS fees — Original title $165; passenger plates $151 per year; battery EV add $100 (standard EV reg $251).
Dealer with $5,000 qualifying trade on $38,000
EV dealer at $30,000
Trade-in, dealer vs private
Qualifying dealer trade-ins reduce the ST-556 taxable base. Private sales do not get a trade-in reduction and do not use 8.75%. Family transfers under the published 2c path can be state $15 (plus RUT-6 exception dollars only where RUT-6 applies). Estate to a surviving spouse can be state $0; other estate beneficiaries often see state $15—still confirm on RUT-50 instructions.
Dealer trade-in
Family 2c gift sketch
Local / NITA / RUT-6
NITA (formerly discussed as RTA in older materials) for titled/registered vehicles in Cook County is reflected as 1.25% inside the Auto Sales structure effective 2026-08-01 per IDOR FY 2026-34. Within Cook County, sampled municipalities share the same Auto Sales High-Rate—unlike general merchandise receipt rates that jump around by city.
Chicago home-rule trap: If the dealer is in Cook, DuPage, Kane, Lake, McHenry, or Will and the purchaser address is the City of Chicago, ST-556 can require an additional 1.25% Chicago Home Rule Use Tax. Always source to the title address.
RUT-6: Yes — Cook County RUT-6, plus Chicago municipal RUT-6 if your address is Chicago.
Confirm Auto Sales in MyTax
RUT-6 reality check
Title and registration fees
| Item | Amount | Notes |
|---|---|---|
| Dealer Auto Sales combined | 8.75% | ST-556; eff. 2026-08-01 |
| NITA titled add-on (structure) | 1.25% | FY 2026-34 |
| Original title | $165 | ILSOS |
| Passenger plates | $151 / yr | ILSOS |
| BEV extra | +$100 / yr | Standard EV reg $251 |
| Duplicate/corrected title | $50 | ILSOS |
Core SOS stack (ICE)
Renewal plates only
Complete worked example
Assumptions match the research brief: ICE passenger; title $165; plates $151; documentary fee $0; purchase on/after 2026-08-01; Auto Sales 8.75%.
Full dealer stack — $30,000
Surviving spouse inheritance sketch
Gifts, out-of-state, renewals
Non-exempt gifts generally use RUT-5 on fair market value. New residents who are individuals bringing a used out-of-state vehicle owned at least three months can see $0 tax under RUT-50 line 1d when the facts fit—SOS fees still due. Illinois home-of-record military members do not get that three-month new-resident exemption automatically; they follow the ordinary path. Out-of-state unregistered dealer purchases may use RUT-25 at the address Auto Sales rate minus credit for tax paid elsewhere.
New resident used OOS ≥ 3 months
OOS credit sketch (RUT-25 style)
FAQ
Is car tax the same as Chicago’s 10%+ store rate?
No. Use Auto Sales High-Rate 8.75% for dealer cars titled in Cook County, not general merchandise.
Private party—same 8.75%?
No. Use the RUT-5 dollar chart; add Cook/Chicago RUT-6 if those guides apply.
Title still $95 or $150?
Plan on $165 for an original title from ILSOS.
Does Illinois charge annual property tax on my car?
Typical consumer titled autos are handled through sales/use tax and SOS fees—not an annual ad valorem car property tax like some states.
Conclusion
For sales tax on cars in Cook County Illinois, start with dealer Auto Sales 8.75% at the title address (effective 2026-08-01), or the RUT-5 chart for private deals, then add title $165 and plates $151. Keep Chicago GM rates, fake private percentages, and outdated title myths out of your estimate. Recheck MyTax and ILSOS before you pay.
This page estimates Cook County vehicle tax and Illinois Secretary of State fees from published IDOR and ILSOS figures. IDOR and the Secretary of State set the amount you actually pay for your address, month, and transfer type.