Connecticut vs Illinois LLC: fees, taxes, and which to pick
Data last updated: Apr 21, 2026Connecticut charges $120 to form an LLC; Illinois charges $150. Day-one sticker price is only part of the story, since most of the real cost comes from the annual obligations that stack up each year you keep the LLC open.
Over a rolling three-year window, Connecticut runs about $15 less in total state fees than Illinois. Whether that gap matters depends on whether you actually operate in one of these states or are weighing a non-resident filing.
On speed, Connecticut typically clears standard online filings faster than Illinois. Both states offer expedited tiers at an additional cost for filers on tight timelines.
For most small operators the choice is not really between these two states at all. It is between forming where the business actually operates and trying to route through a non-resident filing. The data below shows what each option actually costs.
Key differences at a glance
- Connecticut costs $30 less to form ($120 vs $150).
- Illinois is $5 per year cheaper to maintain ($175 vs $180).
Where each state fits
For most filers, forming in the state you actually operate from is the right call. The side-by-side below shows where the two states meaningfully diverge.
Three-year cost, side by side
Rough estimate of the state-facing cost to form and keep an LLC through three years. Both totals include a $100 per year registered-agent estimate.
Running total includes the one-time filing fee and annual ongoing costs (report fee or franchise tax plus a $100/year registered agent estimate).
What it costs under your specific situation
The table below runs the same LLC through four common scenarios. "Non-resident" rows assume a typical home-state foreign LLC registration adds about $200 per year of stacked cost; the real number depends on which state you live in and ranges from $50 to over $800 depending on jurisdiction.
| Scenario | Year 1 | Each year after | 3-year total |
|---|---|---|---|
| You live in Connecticut, business operates there No foreign LLC registration needed. You pay Connecticut fees only. | $300 | $180 | $660 |
| You live in Illinois, business operates there No foreign LLC registration needed. You pay Illinois fees only. | $325 | $175 | $675 |
| Non-resident forming in Connecticut with operations elsewhere You pay Connecticut's fees plus a typical home-state foreign LLC registration of about $200 per year. | $500 | $380 | $1,260 |
| Non-resident forming in Illinois with operations elsewhere You pay Illinois's fees plus a typical home-state foreign LLC registration of about $200 per year. | $525 | $375 | $1,275 |
Connecticut vs Illinois: full comparison
| Dimension | Connecticut | Illinois |
|---|---|---|
| Online filing Can you file the formation document online? | Yes | Yes |
| Online approval time Standard, non-expedited | 5 business days | 10 business days |
| Expedited option Paid fast-track filing | $50 | $100 |
| Annual report Required in addition to tax | Required, $80 | Required, $75 |
| State-imposed annual tax Franchise, privilege, or LLC tax minimum | None | None |
| State income tax On pass-through LLC income at member level | Yes | Yes |
| Publication requirement Newspaper publication after formation | No | No |
| Operating agreement Required by state statute | Recommended, not required | Recommended, not required |
| Foreign LLC fee Cost to register as a foreign LLC in this state | $120 | $150 |
| State sales tax General statewide rate | 6.3% | 6.3% |
Taxes in Connecticut and Illinois
How each state handles entity-level tax on LLCs. Pass-through classification means member-level income tax also applies at each member's residence state.
Connecticut tax
No entity-level franchise tax on LLCs. State income tax applies to member-level pass-through income. Corporate rate 7.5%.
Illinois tax
No entity-level franchise tax on LLCs. State income tax applies to member-level pass-through income. Corporate rate 7.0%.
Ongoing compliance
The recurring filings each state requires after formation.
Connecticut
Annual report $80, due 03/31 each year. Registered agent required in Connecticut.
Illinois
Annual report $75, due on your anniversary month. Registered agent required in Illinois.
Formation process, side by side
What actually happens from the moment you start filing to the moment you're in good standing. Use this as a checklist.
Connecticut
- Check business-name availability on the Connecticut entity search.
- Appoint a registered agent with a physical Connecticut street address.
- File Certificate of Organization (Limited Liability Company, Domestic) for $120.
- Wait for approval. Online typically 5 business days. Paid expedite from $50.
- Adopt an operating agreement (recommended, not required by Connecticut statute).
- Apply for a federal EIN (free from the IRS).
- Open a business bank account to separate personal and business finances.
- File your first annual report and pay $80 when it comes due.
Illinois
- Check business-name availability on the Illinois entity search.
- Appoint a registered agent with a physical Illinois street address.
- File Form LLC-5.5 - Articles of Organization for $150.
- Wait for approval. Online typically 10 business days. Paid expedite from $100.
- Adopt an operating agreement (recommended, not required by Illinois statute).
- Apply for a federal EIN (free from the IRS).
- Open a business bank account to separate personal and business finances.
- File your first annual report and pay $75 when it comes due.
Before you pick either state
A few things that apply no matter which state you choose. These trip up enough first-time filers that they're worth stating explicitly.
Registered agent is non-negotiable. Both Connecticut and Illinois (and every other US state) require every LLC to designate a registered agent with a physical street address in the state of formation. You can serve as your own agent if you live in the state; otherwise a commercial agent runs $50 to $125 per year. Using your own home address makes it part of the public record.
Forming elsewhere does not escape your home state's tax. If you live and operate a business from your home state, forming the LLC in Connecticut or Illinois does not avoid your home state's income tax. The moment you transact business at home, your home state requires a foreign LLC registration, and state tax liability follows your residence regardless of where the entity sits on paper.
EIN applications are free. The IRS issues Employer Identification Numbers directly at no cost. Any service charging you to "get your EIN" is reselling a free form submission. Single-member LLCs with no employees technically don't need one for federal tax, but nearly every bank requires an EIN to open a business account.
Operating agreement matters more than the state you pick. A well-drafted operating agreement governs member ownership, management, profit splits, buy-sell terms, and dissolution. Without one, your LLC runs on the state's default rules, which are rarely what you want. California, Maine, Missouri, and New York require a written one by statute; every other state treats it as strongly recommended.
Agency contacts
Connecticut Secretary of the State, Business Services Division
- Website
- portal.ct.gov/sots
- Phone
- (860) 509-6003
- Business Services Division, P.O. Box 150470, Hartford, CT 06115-0470
- Office
- 165 Capitol Avenue, Suite 1000, Hartford, CT 06106
- Hours
- 8:30 AM to 4:30 PM Eastern, Monday to Friday
Illinois Secretary of State, Department of Business Services
- Website
- www.ilsos.gov/departments/business_services/home.html
- Phone
- (217) 524-8008
- Limited Liability Division, 501 S. Second St., Room 351, Springfield, IL 62756
- Office
- 501 S. Second St., Room 351, Springfield, IL 62756
- Hours
- 8:00 AM to 4:30 PM Central, Monday to Friday
Connecticut Department of Revenue Services
- Website
- portal.ct.gov/drs
- Phone
- (860) 297-5962
- drs@ct.gov
- 450 Columbus Boulevard, Suite 1, Hartford, CT 06103
- Hours
- 8:30 AM to 4:30 PM Eastern, Monday to Friday
Illinois Department of Revenue
- Website
- tax.illinois.gov
- Phone
- (800) 732-8866
- 101 West Jefferson Street, Springfield, IL 62702
- Office
- 555 West Monroe, Suite 1100, Chicago, IL 60661
- Hours
- 8:30 AM to 5:00 PM Central, Monday to Friday
Frequently Asked Questions
-
Is it cheaper to form an LLC in Connecticut or Illinois?
Connecticut is cheaper at formation ($120) than Illinois ($150). Ongoing costs are also different: $180 vs $175 per year. Total over three years: $660 vs $675.
-
Can I form an LLC in Connecticut if I live in Illinois?
Yes, but your Illinois business will almost certainly need to register as a foreign LLC in Illinois too, which means paying Illinois's foreign registration fee and any ongoing Illinois obligations on top of the Connecticut ones. The "form elsewhere to save" math usually doesn't work for operating businesses; it only works when you have no physical operations tied to any specific state.
-
How long does it take to form an LLC in Connecticut vs Illinois?
Connecticut online: 5 business days; Illinois online: 10 business days. Connecticut offers paid expedite from $50. Illinois offers paid expedite from $100.
-
Which state has lower taxes for an LLC, Connecticut or Illinois?
Connecticut: state income tax applies to member-level pass-through income, no entity-level franchise or LLC tax. Illinois: state income tax applies to member-level pass-through income, no entity-level franchise or LLC tax.
-
Do both states require a registered agent?
Yes. Every US state (and DC) requires every LLC to maintain a registered agent with a physical street address in the state. Connecticut and Illinois both have this requirement. You can serve as your own agent if you live in the state; most out-of-state filers use a commercial agent for $50 to $125 per year.
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Which state should I pick if I run an online business from home?
Form in the state you actually live in. Your home state's Department of Revenue treats your residence as nexus regardless of where the LLC is filed, which means you owe state income tax there anyway. Forming in Connecticut or Illinois to escape your home state's tax doesn't work; it adds paperwork. The non-resident filings make sense when you genuinely operate nowhere in particular: international founders, purely passive holding entities, or real-estate LLCs owning property in other states.
Full state guides
More Connecticut and Illinois comparisons
More Connecticut vs ...
Sources
- Filing fee: business.ct.gov/knowledge-base/articles/domestic-limited-liability-com… · verified April 21, 2026
Connecticut Secretary of the State Business Services: Certificate of Organization (formation of a domestic LLC) fee is $120. Same fee applies whether filed online through Business.CT.gov or by mail. - Expedited filing: business.ct.gov/knowledge-base/articles/expedited-services · verified April 21, 2026
Connecticut expedited service fee is $50 per transaction. Expedited service is only available for online filings through Business.CT.gov (not available for mail). Expedited filings typically process within 24 hours. - Annual report fee: business.ct.gov/knowledge-base/articles/domestic-limited-liability-com… · verified April 21, 2026
Annual Report fee = $80, filed online between January 1 and March 31 each year. Same $80 fee applies to foreign LLCs (Foreign Annual Report). - Franchise tax: www.cttaxalert.com/2019/08/business-entity-tax-repeal/ · verified April 21, 2026
Connecticut Public Act 19-117 (2019 budget bill) repealed the $250 biennial Business Entity Tax (Conn. Gen. Stat. Sec. 12-284b) effective for tax years beginning on or after January 1, 2020. Connecticut no longer imposes a franchise tax or business entity tax on LLCs. Flagged as applies: false per the instructions. - Foreign LLC registration fee: business.ct.gov/knowledge-base/articles/foreign-limited-liability-comp… · verified April 21, 2026
Connecticut Foreign Registration Statement (foreign LLC): $120 filing fee, matching the domestic Certificate of Organization. Foreign LLCs also file the $80 Annual Report between January 1 and March 31. - Sales tax rate: portal.ct.gov/drs/sales-tax/sales-and-use-tax-information · verified April 21, 2026
Connecticut Department of Revenue Services: statewide general sales and use tax rate is 6.35%. Connecticut does not authorize local sales taxes. A higher 7.75% rate applies to certain luxury goods and a 1% rate applies to computer and data processing services. - Corporate income tax rate: portal.ct.gov/drs/corporation-tax/corporation-business-tax · verified April 21, 2026
Connecticut Corporation Business Tax (CBT) base rate is 7.5% on net income. A 10% CBT surtax has been extended through income years beginning before January 1, 2026 by Public Act 24-151. The 7.5% is Connecticut's income-only corporate rate; the surtax and PTET are noted in taxes.notes rather than folded into this number. - Business name search: service.ct.gov/business/s/onlinebusinesssearch?language=en_US · verified April 21, 2026
Connecticut Business Records Search via the CT.gov portal. Use before filing to confirm name availability. - Online filing portal: business.ct.gov/ · verified April 21, 2026
Business.CT.gov is the official online filing portal for Connecticut business formation, annual reports, and amendments. Filings typically complete within 3 to 5 business days (standard) or about 1 business day with the $50 expedited fee. - Operating agreement requirement: law.justia.com/codes/connecticut/title-34/chapter-613a/section-34-243d… · verified April 21, 2026
Conn. Gen. Stat. Sec. 34-243a defines an operating agreement as the agreement of all members whether oral, implied, in a record, or any combination. No statutory requirement that the agreement be written or filed. Recorded as not required. - Publication requirement: law.justia.com/codes/connecticut/title-34/chapter-613a/ · verified April 21, 2026
Connecticut Uniform Limited Liability Company Act (Chapter 613a) contains no newspaper publication requirement. LLCs are not required to publish notice of formation. - Filing fee: law.justia.com/codes/illinois/chapter-805/act-805-ilcs-180/article-50/… · verified April 21, 2026
805 ILCS 180/50-10(b)(1): 'Filing articles of organization (domestic), application for admission (foreign), and restated articles of organization (domestic), $150.' Series LLC formation fee is $400 under the same subsection. - Expedited filing: law.justia.com/codes/illinois/chapter-805/act-805-ilcs-180/article-50/… · verified April 21, 2026
805 ILCS 180/50-50(e): Expedited fees include Articles of Organization $100, Articles of Amendment $100, Reinstatement $100, Application for Admission $100, Merger $200, Restated Articles $200. 24-hour turnaround for most expedited services. - Online filing portal: apps.ilsos.gov/llcarticles/index.jsp · verified April 21, 2026
Illinois Secretary of State online Articles of Organization filing portal. - Certificate of Formation form: www.ilsos.gov/publications/business-services/llc.html · verified April 21, 2026
Form LLC-5.5 Articles of Organization. PDF hosted at https://www.ilsos.gov/publications/pdf_publications/llc55.pdf - Business name search: apps.ilsos.gov/corporatellc/ · verified April 21, 2026
Illinois Secretary of State business entity search. - Operating agreement requirement: law.justia.com/codes/illinois/chapter-805/act-805-ilcs-180/article-1/ · verified April 21, 2026
805 ILCS 180/1-5 defines 'operating agreement' as an agreement 'whether oral, in a record, implied, or in any combination thereof.' No statutory requirement for a written operating agreement. - Publication requirement: law.justia.com/codes/illinois/chapter-805/act-805-ilcs-180/ · verified April 21, 2026
805 ILCS 180 imposes no newspaper publication requirement for LLC formation. - Foreign LLC registration fee: law.justia.com/codes/illinois/chapter-805/act-805-ilcs-180/article-50/… · verified April 21, 2026
805 ILCS 180/50-10(b)(1): Application for Admission (foreign LLC) fee is $150, same as domestic Articles of Organization. - Annual report fee: law.justia.com/codes/illinois/chapter-805/act-805-ilcs-180/article-50/… · verified April 21, 2026
805 ILCS 180/50-10(b)(11): Annual report fee $75, plus $50 per series for series LLCs. 805 ILCS 180/50-15(b)(1) penalty: $100 plus $100 for each year of delinquency. Deadline is before the first day of the anniversary month (§50-1(b)). - Franchise tax: tax.illinois.gov/research/taxrates/income.html · verified April 21, 2026
Illinois phased out the corporate franchise tax effective January 1, 2024 (P.A. 102-16). LLCs classified as partnerships pay Personal Property Replacement Tax at 1.5% of net income, but this is not classified as a franchise tax. No franchise tax applies to LLCs. - Corporate income tax rate: tax.illinois.gov/research/taxrates/income.html · verified April 21, 2026
Illinois corporate income tax is 7% of net income, plus 2.5% Personal Property Replacement Tax, for a combined 9.5% rate on C-corporation income. Individual income tax is 4.95% (flat). - Sales tax rate: tax.illinois.gov/questionsandanswers/answer.139.html · verified April 21, 2026
Illinois state general merchandise sales tax rate is 6.25%. Effective January 1, 2026, the 1% state grocery tax was eliminated. Local jurisdictions may impose additional taxes; combined rates vary by location.