Consultants in Montana: taxes and retirement for 2026
For independent consultants and fractional executives billing clients directly in Montana. Montana has a graduated state income tax for 2026: 4.7% to 5.65% (top rate starts at $47,500 for single filers). Here are the 2026 rules, a worked example and the official sources.
Montana rules for consultants
- State income tax (2026)
- Montana has a graduated state income tax for 2026: 4.7% to 5.65% (top rate starts at $47,500 for single filers). Under HB 337 (2025), single filers pay 4.7% on taxable income up to $47,500 and 5.65% above it. The breakpoint is $95,000 for joint filers and $71,250 for heads of household. For 2027, the 4.7% bracket widens to $65,000 (single) and the top rate drops to 5.4%. Long-term capital gains stay at 3.0%/4.1%.
- State estimated tax
- You must make estimated payments if you expect to owe $500 or more in Montana income tax after withholding and credits, for example from self-employment income. Same dates as federal (April 15, June 15, September 15, January 15). Form Form IT (Montana Individual Income Tax Payment Voucher) or online via TAP.
- Independent contractor test and Independent Contractor Exemption Certificate (ICEC) program
- To be an independent contractor in Montana, a worker must be free from control or direction, run their own independently established business, and either hold an ICEC or carry self-elected workers' compensation coverage. The ICEC costs a non-refundable $125, no test is required, and violations can bring fines of up to $5,000.
- ICEC requirements and effect (MCA 39-71-417)
- Sole proprietors, partners, and LLC members who regularly work away from their own fixed business location (including in construction) must get an ICEC unless they elect workers' comp coverage. The certificate lasts 2 years. Holders are conclusively presumed to be independent contractors and give up workers' comp benefits unless they elected coverage.
Federal rules for 2026
Solo 401(k) up to $72,000
A one-person consultancy can contribute a $24,500 employee deferral plus an employer share of about 20% of net self-employment earnings, up to $72,000 in 2026, plus an $8,000 catch-up at 50 or older ($11,250 at ages 60 to 63).
The S-corp trade-off
Electing S-corp status can cut payroll tax, but the salary you pay yourself also sets your Solo 401(k) room. Run both sides before you elect.
Quarterly estimated taxes
No one withholds tax from self-employment income, so you generally pay estimates four times a year if you expect to owe $1,000 or more. For 2026 income the federal dates are April 15, June 15 and September 15, 2026, and January 15, 2027. Paying 100% of last year's tax (110% if your AGI was over $150,000) in four equal installments avoids the underpayment penalty.
Self-employment tax
On top of income tax, self-employed people pay 15.3% on 92.35% of net profit: 12.4% Social Security up to the 2026 wage base of $184,500, plus 2.9% Medicare with no cap. Half of it is deductible.
A worked example
| Self-employment tax (sole proprietor) | $21,194 |
|---|---|
| Solo 401(k) maximum | $52,381 |
| SEP IRA maximum | $27,881 |
| Payroll tax saved as an S-corp on a $75,000 salary | $9,719 |
| Solo 401(k) maximum as that S-corp | $43,250 |
Federal figures only, before state and local taxes. Simplified: excludes the QBI deduction and the 0.9% Additional Medicare Tax. Computed from 2026 IRS limits (Notice 2025-67, Rev. Proc. 2025-32) and the SSA wage base.
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Questions
Do consultants in Montana pay state income tax?
Montana has a graduated state income tax for 2026: 4.7% to 5.65% (top rate starts at $47,500 for single filers). Under HB 337 (2025), single filers pay 4.7% on taxable income up to $47,500 and 5.65% above it. The breakpoint is $95,000 for joint filers and $71,250 for heads of household. For 2027, the 4.7% bracket widens to $65,000 (single) and the top rate drops to 5.4%. Long-term capital gains stay at 3.0%/4.1%.
When are Montana estimated tax payments due for 2026?
You must make estimated payments if you expect to owe $500 or more in Montana income tax after withholding and credits, for example from self-employment income. Same dates as federal (April 15, June 15, September 15, January 15). The state form is Form IT (Montana Individual Income Tax Payment Voucher) or online via TAP.
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Sources
- revenue.mt.gov/news/recent-news/HB-337
- revenue.mt.gov/taxes/estimated-tax-payments
- erd.dli.mt.gov/labor-standards/wage-and-hour-payment-act/state-minimum-wage
- erd.dli.mt.gov/work-comp-regulations/montana-contractor/independent-contractor
- mca.legmt.gov/bills/mca/title_0390/chapter_0710/part_0040/section_0170/0390-0710-0040-0170.html
State and local facts researched from official sources and independently re-checked; last verified October 2026, next scheduled review 2027-01-02. Educational information for 2026, not tax, legal or investment advice. Rules change; check the official sources listed and a tax professional for your situation. Gigaverse AI, Inc. is a financial technology company, not a bank, and not itself a registered investment adviser or broker-dealer.