Starting a business in Idaho costs as little as $100 for an LLC filing fee. The state income tax rate is up to 5.7%, with a 5.8% corporate tax rate. Below we compare LLC vs. S-Corp vs. Sole Proprietorship costs, walk through the 6 steps to form your business, and provide calculators pre-filled for Idaho.
LLC vs. S-Corp vs. Sole Proprietorship — 2026 estimated costs
| Entity Type | Filing Fee | Annual Fee | Franchise Tax | 1st Year Total | Ongoing/Yr |
|---|---|---|---|---|---|
| LLC | $100 | -- | -- | $225 | $125/yr |
| S-Corp | $100 | $50 | -- | $275 | $175/yr |
| Sole Proprietorship | $30 | -- | -- | $30 | -- |
No annual LLC fee but requires annual report. Business-friendly regulatory environment.
Your LLC name must be unique in Idaho and include"LLC" or"Limited Liability Company." Search the Idaho Secretary of State database to verify availability. Consider reserving the name (typically $10-25 for 60-120 days) while you prepare your filing.
File your Articles of Organization (or Certificate of Formation) with the Idaho Secretary of State. The filing fee is $100. You can file online in most states for faster processing. Include your registered agent information, member names, and business purpose.
Apply for a free Employer Identification Number (EIN) from the IRS at irs.gov. You need this for opening a bank account, hiring employees, and filing taxes. The online application takes about 5 minutes and you receive your EIN immediately.
Register with the Idaho Department of Revenue for state income tax withholding and sales tax collection (6.0% state rate). If you have employees, register for unemployment insurance and workers' compensation. The state income tax rate is up to 5.7%.
Check Idaho and local requirements for business licenses, professional licenses, and permits. Requirements vary by industry and location. Common needs include a general business license, zoning permit, and industry-specific permits (food service, construction, healthcare, etc.).
Open a dedicated business bank account to maintain your LLC's liability protection. You may need your Articles of Organization, EIN, and operating agreement. Keep personal and business finances strictly separate — commingling funds can pierce the corporate veil and expose personal assets.
Total estimated first-year cost: $225 (filing fee + registered agent + annual fees). Ongoing annual cost is approximately $125/yr after the first year.
Idaho's COL index of 99 is essentially the national average, though Boise has risen above 105 due to rapid growth.
Sun Valley / Ketchum areas have a COL that's 150%+ of the national average — a pocket of extreme cost.
Idaho's flat 5.8% income tax rate is moderate. The state recently moved from a progressive system to a flat rate.
Idaho taxes Social Security benefits following federal rules — up to 85% may be taxable depending on income.
Idaho's sales tax is 6% with no local additions, making it simpler than many states.
National averages based on mean of all 50 states + DC. "pp" = percentage points.
The Idaho LLC filing fee is $100. Including a registered agent ($125/yr), the first-year total cost is approximately $225. This is $32 below the national average filing fee.
An LLC is simpler and cheaper to maintain in Idaho ($225 first-year cost vs. $275 for an S-Corp). An S-Corp can save self-employment taxes if you earn over ~$50K in profit by splitting income into salary and distributions. Most Idaho businesses start as an LLC and elect S-Corp taxation later when profits justify the additional complexity and payroll costs.
Idaho businesses face: personal income tax on pass-through income (up to 5.7%), corporate income tax at 5.8% for C-Corps, sales tax at 6.0%, payroll taxes, and property tax at 0.7% on business-owned real estate.
Requirements vary by business type and location. Most Idaho businesses need: (1) a state business license or registration, (2) a local business license from your city/county, (3) industry-specific permits or professional licenses, and (4) a sales tax permit if selling taxable goods. Check with the Idaho Secretary of State and your local city clerk for specific requirements.
Business formation costs are estimates based on Idaho Secretary of State fees as of 2026. Tax rates use 2026 data. Registered agent fees based on market averages. Actual costs may vary. Consult a CPA or business attorney for personalized advice. Last updated: April 2026.