Self-Employed · Freelancers · 1099

Idaho Solo 401(k) Calculator 2026

Your exact contribution limit and combined federal + Idaho state tax savings. Free, no sign-up.

Idaho state tax

5.8% State Rate

2026 max contribution

$70,000

Est. total savings*

$11,676

Deadline to open

Dec 31, 2026

*Based on $42,000 contribution at 22% federal + 5.8% state rate

Idaho tax note: Idaho levies a 5.8% state income tax. Your Solo 401(k) contributions reduce both your federal and Idaho taxable income, boosting your total tax savings beyond the federal benefit alone.

Your situation

Takes under 2 minutes · We never store your inputs

✦ Import from document

Paste an offer letter, 1099, contract, or any document with income details — Claude will fill the fields for you.

Affects catch-up contribution limits (age 50+, 60–63 enhanced)

From Schedule C line 31, or your best estimate if mid-year

Enter 0 if you have no day job. Affects IRA deductibility and total 401(k) room.

An HDHP (high-deductible plan) unlocks HSA contributions — the only triple-tax-advantaged account

Traditional IRA, SEP-IRA, or SIMPLE IRA balances. Affects backdoor Roth eligibility.

We never store your inputs. All calculations happen on our server.

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Your 2026 retirement plan

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Solo 401(k) Tax Savings in Idaho

Idaho levies a 5.8% state income tax. Your Solo 401(k) contributions reduce both your federal and Idaho taxable income, boosting your total tax savings beyond the federal benefit alone.

At 5.8% Idaho income tax plus 22% federal, a $42,000 Solo 401(k) contribution saves approximately $11,676 in combined taxes — $9,240 federal and $2,436 state. That's a 27.8% combined tax savings rate on every dollar contributed.

How to open a Solo 401(k) as a Idaho freelancer

  1. Get an EIN — free at IRS.gov, takes 5 minutes. Required even as a sole proprietor.
  2. Choose a provider — Fidelity, Schwab, and Vanguard offer free Solo 401(k) plans with no annual fees.
  3. Open by December 31 — the account must exist before year-end for contributions to count for that tax year.
  4. Fund by your filing deadline — April 15, 2027, or October 15 with an extension.

Frequently Asked Questions

How much can a self-employed Idaho resident contribute in 2026?

The 2026 Solo 401(k) limit is $70,000 ($77,500 with catch-up for those 50+). Your exact maximum depends on your net self-employment income after the SE tax deduction. Use the calculator above for your specific number.

Does Idaho tax Solo 401(k) contributions?

Idaho follows the federal treatment. Traditional (pre-tax) contributions reduce your Idaho taxable income at the 5.8% state rate, providing savings at both the federal and state level.

Solo 401(k) vs. SEP-IRA — which is better for Idaho freelancers?

For most Idaho self-employed professionals earning under $280,000, a Solo 401(k) allows larger contributions than a SEP-IRA — especially at income under $120,000. Both receive the same Idaho state tax treatment on contributions.

When is the Solo 401(k) deadline for Idaho residents?

The account must be open by December 31, 2026. Employee deferrals are elected by year-end. Employer contributions can be made up to your tax filing deadline — April 15, 2027, or October 15 with an extension.

Solo 401(k) guides by state

All states →UtahWashingtonOregon

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