Auto Repair Shop Retirement Plans: Solo 401(k), SIMPLE IRA, and the Employer Contribution Credit

By Yarik Yarosh, CPA ·September 5, 2026 ·5 min read

Written by Yarik Yarosh, CPA (US & Canada) September 5, 2026 · FL CPA license AC61704 · CPA Ontario

Auto repair shop owners often neglect retirement planning because the business demands constant reinvestment in equipment, parts inventory, and employees. However, retirement plan contributions are one of the most powerful tax deductions available: they reduce taxable income dollar-for-dollar, grow tax-deferred, and the SECURE 2.0 tax credit can offset the cost of setting up and maintaining the plan.

✓Key takeaway

Retirement plan options for auto repair shops:

Solo 401(k) (owner-only shop, no full-time employees other than spouse):

2025 limits: $23,500 employee deferral + 25% of net SE income (up to $70,000 total)
Catch-up: $7,500 (age 50+) or $11,250 (ages 60-63, SECURE 2.0 super catch-up)
Roth option available
Allows loans from the plan (up to $50,000 or 50% of balance)
Cannot be used once the shop hires full-time employees (other than spouse)

SIMPLE IRA (shops with employees):

2025 limits: $16,500 employee deferral + mandatory employer match (up to 3% of compensation) or 2% non-elective contribution
Available to businesses with up to 100 employees
Lower administrative costs than a full 401(k)
No plan loans
25% early withdrawal penalty for first 2 years (instead of the standard 10%)

Traditional 401(k) (larger shops with multiple employees):

Same limits as Solo 401(k) for the owner ($23,500 + employer contribution)
Requires nondiscrimination testing (or safe harbor provisions to avoid testing)
Higher administrative costs ($1,000-$3,000/year)
Most flexible: allows vesting schedules, loans, Roth contributions

How does the plan choice change as the shop grows?

Hypothetical example

Round numbers. For current guidance, see IRS Retirement Plans for Small Business. A shop owner starts as a one-person operation, then hires mechanics.

Year 1: Owner only, $120,000 net S-Corp salary + $40,000 pass-through

Solo 401(k) contribution: $23,500 (employee) + $30,000 (employer, 25% of salary) = $53,500
Tax savings: $53,500 x 32% = $17,120
SECURE 2.0 startup credit: $5,000 (Year 1)

Year 3: Owner + 2 full-time mechanics (must switch from Solo 401(k))

Switch to SIMPLE IRA
Owner contribution: $16,500 (employee deferral)
Employer match: 3% of each employee’s compensation
- Owner match: $65,000 salary x 3% = $1,950
- Mechanic A match: $50,000 x 3% = $1,500
- Mechanic B match: $45,000 x 3% = $1,350
Total employer match cost: $4,800 (tax-deductible)
Owner’s total retirement savings: $16,500 + $1,950 = $18,450
Tax savings on owner’s contributions: $18,450 x 32% = $5,904
SECURE 2.0 employer contribution credit: $1,000/employee x 2 mechanics = $2,000

The contribution limit drops from $53,500 (Solo 401(k)) to $18,450 (SIMPLE IRA). This is the trade-off of hiring employees. A traditional 401(k) with safe harbor provisions would allow up to $70,000 in total contributions but at higher administrative cost.

Illustrative numbers only, not a real client and not advice for your facts.

Why does the shop’s non-SSTB status matter for retirement?

Because auto repair is NOT an SSTB, the QBI deduction is available at all income levels. Retirement plan contributions reduce taxable income, which reduces the income tax on the pass-through profits. But the QBI deduction is calculated on Qualified Business Income before retirement plan deductions (QBI is calculated at the entity level, while retirement contributions are taken on the individual return).

This means the QBI deduction and the retirement plan deduction stack: a shop owner with $85,000 in pass-through income gets a $17,000 QBI deduction (20%) AND a retirement plan deduction of up to $53,500. They do not reduce each other.

Can I set up a retirement plan if I have variable self-employment income?

Yes, and several plan types accommodate variable income well. A SEP-IRA allows contributions of up to 25% of net self-employment income with no required annual contribution, so you can skip a year or reduce contributions when income drops. A solo 401(k) provides the same flexibility for employer contributions, plus an employee deferral of up to $23,000 (2024) regardless of income level (as long as you have at least that much in compensation). A SIMPLE IRA requires a fixed employer match or contribution each year, making it less ideal for variable income. The key is choosing a plan that does not lock you into contributions you cannot afford in a lean year.

Related guides:

Retirement Plan Startup Tax Credit: Up to $15,000 for New 401(k) or SIMPLE Plans (SECURE 2.0)
Moving Company Retirement Plans: Solo 401(k) for Owner-Operators, SIMPLE IRA for Crews
Daycare Center Retirement Plans: SIMPLE IRA for Staff-Heavy Centers and the Employer Contribution Credit
Small Business Retirement Plans: Solo 401(k) vs. SEP IRA vs. SIMPLE IRA (2025)
Retirement Plans for Pet Grooming Business Owners: Solo 401(k) and Plans with…
SEP IRA vs. Solo 401(k) vs. SIMPLE IRA: Retirement Plan Comparison for Small …

What are the catch-up contribution rules for business owners over 50?

Business owners aged 50 and older can make additional catch-up contributions beyond the standard limits for most qualified retirement plans. For 401(k) plans including solo 401(k)s, the catch-up contribution is an additional $7,500 for 2025 on top of the standard $23,500 employee deferral limit. SEP IRAs don’t have catch-up provisions because contributions are employer-only and already allow up to 25% of compensation or $70,000. SIMPLE IRAs permit a $3,500 catch-up for those 50 and older, and starting in 2025, participants aged 60-63 get an enhanced catch-up of $5,000 under the SECURE 2.0 Act.

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Cite this page

Yarik Yarosh, CPA. "Auto Repair Shop Retirement Plans: Solo 401(k), SIMPLE IRA, and the Employer Contribution Credit." Blue Cloud CPA, September 5, 2026. https://bluecloudcpa.com/guides/auto-repair-shop-retirement-plans

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.