On most purchases, sales tax in Wisconsin vs. Illinois comes down to this: Wisconsin charges a flat 5% state rate with a small county add-on, while Illinois starts at 6.25% and lets cities, counties, and transit districts stack on top of it. That gap widens or narrows depending on what you’re buying and where. Groceries in Wisconsin are tax-free; the same cart in Chicago still carries local taxes even after the 2026 state repeal. Services taxed in Wisconsin often aren’t taxed in Illinois at all. And a single receipt in Chicago can cross 10% while the same purchase 40 miles north sits at 5.5%.
What You Actually Pay by Location
Wisconsin’s base rate is 5%.1Department Of Revenue. Tax Rates Seventy of its 72 counties add a 0.5% county tax, so most of the state runs at a combined 5.5%. Milwaukee County is the outlier: its county surcharge rose to 0.9% on January 1, 2024, putting purchases there at 5.9%.2Wisconsin Department of Revenue. County and City Sales and Use Taxes Cities don’t add their own sales tax on top.
Illinois begins at 6.25% under the Retailers’ Occupation Tax Act,3Illinois General Assembly. 35 ILCS 120/2-13 – Remote Retailer Amnesty Program and from there the layering starts. Municipalities, counties, home-rule jurisdictions, and transit districts can each pile on. The Regional Transportation Authority levies its own surcharge across the six-county Chicago region, and in late 2025 the Northern Illinois Transit Authority Act authorized an additional 0.25% RTA sales tax across that same area.4Regional Transportation Authority. Moving the System Combine everything and general merchandise in Chicago runs at least 10.25%, with the new surcharge potentially pushing it higher.5Illinois Department of Revenue. Mass Transit District Sales Tax
Rural Illinois sits well below Chicago, but even small towns can land near 8% or 9% once home-rule and county taxes stack. So the real comparison isn’t Wisconsin vs. Illinois in the abstract. It’s Wisconsin’s fairly uniform 5.5% against whatever specific Illinois jurisdiction you happen to be standing in.
Groceries and Medicine
This is where the two states diverge most, and where Illinois shoppers saw the biggest change in 2026.
Wisconsin: Fully Exempt
Wisconsin exempts food and food ingredients intended for home consumption from sales tax entirely.6Wisconsin State Legislature. Wisconsin Code 77.54 – General Exemptions The exemption wipes out the state tax and the county surcharge. Prescription drugs and certain medical devices are also fully exempt. Candy, soft drinks, dietary supplements, and prepared food don’t qualify and are taxed at the full rate.7Wisconsin State Legislature. Wisconsin Administrative Code Tax 11.51
Illinois: State Tax Gone, Local Taxes Often Not
Before 2026, Illinois taxed qualifying groceries at a reduced 1% state rate. Public Act 103-0781 eliminated that state-level tax on January 1, 2026. The headline sounds like parity with Wisconsin, but the same law lets municipalities and counties impose their own 1% grocery tax by ordinance, and hundreds of local governments did so quickly. The RTA’s existing 1% grocery surcharge in the six-county Chicago region also stayed in place.8Illinois Department of Revenue. Illinois Grocery Tax Changes Effective January 1, 2026 So an Illinois grocery bill may still carry local tax even though the state’s share is gone.
Candy, soft drinks, cannabis-infused food, and prepared food remain taxable at the full 6.25% state rate plus local add-ons.9Legal Information Institute. Ill. Admin. Code tit. 86, 130.310 – Food, Soft Drinks and Candy Prescription and qualifying nonprescription drugs and medical appliances stay at the 1% reduced rate.10Legal Information Institute. Ill. Admin. Code tit. 86, 140.126 – Taxation of Food, Drugs and Medical Appliances That means Wisconsin is still the cheaper state at the pharmacy counter, even after Illinois’s grocery repeal.
Services: The Reversal
Anyone comparing only rates on merchandise misses the biggest structural difference. Wisconsin taxes a broad list of services; Illinois generally doesn’t.
Wisconsin collects sales tax on landscaping and lawn care, dry cleaning and laundry, repair of tangible personal property, photography, towing, parking, boat docking and storage, cable television, telecommunications, and admissions to entertainment or sporting events.11Wisconsin Department of Revenue. What Is Taxable Hire a landscaper in Wisconsin and the full state and county rate applies to the bill.
Illinois imposes its sales tax primarily on tangible personal property. If a service provider transfers physical goods as part of the job — say, replacement parts during a repair — tax applies to those goods, but not to the labor.12Illinois Department of Revenue. Sales and Use Taxes The same landscaping job in Illinois wouldn’t carry state sales tax on the service charges. For people living near the border and hiring recurring service work, this can outweigh the difference on merchandise.
Buying a Vehicle Across the Border
You can’t skip tax by dealer-shopping. Vehicles are taxed based on where you register and title them, not where you buy. An Illinois resident buying at a Wisconsin dealer owes Illinois tax at registration, and a Wisconsin resident buying in Illinois owes Wisconsin’s.
Credit for Tax Already Paid
Both states credit sales or use tax paid to the other, so you aren’t taxed twice. Wisconsin lets tax paid to another state offset what you’d otherwise owe at registration, but if you paid more elsewhere than Wisconsin would charge, you don’t get a refund of the excess.13Wisconsin State Legislature. Wisconsin Administrative Code Tax 11.83 Illinois residents who buy out of state file Form RUT-25 when bringing the vehicle in and claim credit the same way.14Illinois Department of Revenue. Illinois Tax Requirements for Cars, Trucks, Vans, Motorcycles, ATVs
Moving in? Illinois waives tax if you owned and titled the vehicle in another state for more than three months before establishing Illinois residency, though you still file Form RUT-25.14Illinois Department of Revenue. Illinois Tax Requirements for Cars, Trucks, Vans, Motorcycles, ATVs Wisconsin has a similar rule: a nonresident who bought a vehicle outside Wisconsin at least 90 days before moving in is exempt from Wisconsin use tax on it.13Wisconsin State Legislature. Wisconsin Administrative Code Tax 11.83
Trade-Ins
Both states let a dealer trade-in reduce the taxable price with no dollar cap. In Wisconsin, tax applies only to the difference between the purchase price and the trade-in value, and you can trade in more than one vehicle against a single purchase.13Wisconsin State Legislature. Wisconsin Administrative Code Tax 11.83 Illinois previously capped the trade-in credit at $10,000; that cap was removed effective January 1, 2022. The trade-in deduction is not available on private-party purchases reported on Form RUT-50.15Illinois Department of Revenue. Vehicle Tax FAQs
Cross-Border Shopping and Use Tax
If you live near the state line, use tax is the rule that closes the obvious loophole. Buy something across the border and your home state expects you to pay the difference.
Illinois residents who buy in Wisconsin at 5.5% owe Illinois the gap up to their local use tax rate, which starts at 6.25% and rises with local add-ons. If your total annual use tax is $600 or less, report it on Form IL-1040 by April 15. Above $600, it’s due monthly, by the last day of the month after purchase.16Illinois Department of Revenue. Use Tax for Individuals – Questions and Answers
Wisconsin residents owe the same thing in reverse when they bring taxable goods home from Illinois, with credit for tax already paid.17Wisconsin Department of Revenue. Wisconsin Use Tax – Fact Sheet 2104 Because most Illinois jurisdictions charge more than Wisconsin, a Wisconsinite who shopped in Illinois has usually already overpaid from Wisconsin’s perspective and owes nothing further.
Enforcement isn’t hypothetical. The Illinois Department of Revenue gathers purchase data from other states and bills residents for unpaid use tax with penalties and interest.16Illinois Department of Revenue. Use Tax for Individuals – Questions and Answers Occasional small purchases rarely draw attention, but repeated cross-border buying of appliances, electronics, or other high-ticket items should be reported.
Online Orders
Since South Dakota v. Wayfair in 2018, both states require out-of-state online sellers to collect sales tax once they cross a sales threshold. Wisconsin’s threshold is $100,000 in gross sales into the state in the current or previous calendar year.18Wisconsin Department of Revenue. Remote Sellers – Wayfair Decision Illinois uses the same $100,000 threshold on a rolling 12-month lookback ending each calendar quarter. Marketplace platforms like Amazon and eBay collect on behalf of third-party sellers regardless of the individual seller’s volume.19Wisconsin Department of Revenue. Marketplace Provider Common Questions
In practice, checkout tax follows your delivery address. An order shipped to Kenosha carries Wisconsin’s rate; the same order shipped to Waukegan carries Illinois’s rate, local add-ons included. Purchases from smaller sellers that fall below the thresholds and don’t collect at checkout still trigger use tax on your end.
Side-by-Side Summary
- Base state rate: Wisconsin 5%, Illinois 6.25%.
- Typical combined rate: Wisconsin 5.5% in most counties, 5.9% in Milwaukee County; Illinois ranges from 6.25% in areas with no local add-ons to more than 10% in Chicago.
- Groceries in 2026: Wisconsin fully exempt; Illinois state tax repealed, but many local governments and the RTA still tax groceries at 1%.
- Candy, soft drinks, and prepared food: taxable at full rates in both states.
- Prescription drugs: exempt in Wisconsin, 1% in Illinois.
- Services: Wisconsin taxes landscaping, dry cleaning, repairs, photography, parking, and more; Illinois generally does not tax service labor.
- Vehicle trade-ins at a dealership: full value reduces the taxable price in both states, with no cap.
For anyone splitting time between the two states, Wisconsin offers simpler math and lower rates on almost everything except services. Illinois’s total rate depends heavily on where you’re standing, and the grocery picture is messier than the repeal headlines suggest. Before a major purchase, checking your specific jurisdiction’s combined rate is the two-minute step worth taking.