Retirement Planning

The Solo 401(k) is the most flexible and highest-contribution option for self-employed individuals with no employees. You can contribute $23,500 as an employee deferral plus 25% of net SE income as an employer contribution, for a combined maximum of $69,000 for 2026 (plus $7,500 catch-up if 50+, or $11,250 enhanced catch-up if 60-63 under SECURE 2.0). The SEP-IRA is simpler to administer but limited to the employer contribution only (25% of net SE, up to $69,000). SIMPLE IRAs work for those with employees. Traditional and Roth IRAs provide an additional $7,000 ($8,000 if 50+). Deadlines differ: Solo 401(k) employee deferrals must be made by 31 December; employer contributions and SEP-IRA contributions can be made by the return filing deadline including extensions.

TaxKiln Editorial · Last reviewed: June 1, 2026

Self-employed individuals have access to retirement plan options that are, in many ways, more powerful than what W-2 employees receive. A sole proprietor with no employees can contribute up to $69,000 per year to a Solo 401(k) in 2026 — more than most employer-sponsored plans allow — and the entire contribution is tax-deductible, reducing both income tax and the basis for the QBI deduction calculation. Combined with a Health Savings Account, a self-employed person can shelter over $73,000 per year from taxation. Yet the majority of self-employed individuals either have no retirement plan or contribute far less than they could, because the options are confusing and the deadlines vary by plan type. This guide compares every retirement plan available to the self-employed, explains the contribution limits and deadlines, and models the tax savings for a real scenario.

Key mechanics

Solo 401(k): the most powerful option for self-employed individuals without employees

The Solo 401(k), also called the individual 401(k) or one-participant 401(k), is available to self-employed individuals with no common-law employees other than a spouse. It combines two contribution types: an employee elective deferral and an employer profit-sharing contribution. For 2026, the employee deferral limit is $23,500 (the same limit that applies to traditional employer 401(k) plans under IRC Section 402(g)). The employer contribution is up to 25% of net self-employment income (defined as net SE earnings minus 50% of SE tax, under IRC Section 401(c)(2)).

The combined employee + employer contribution cannot exceed $69,000 for 2026 (the annual additions limit under IRC Section 415(c)). Catch-up contributions are available: $7,500 for ages 50 and older, and under SECURE 2.0 Section 109, an enhanced catch-up of $11,250 for ages 60-63. This means a 61-year-old sole proprietor with sufficient SE income can contribute up to $80,250 in a single year.

The Solo 401(k) offers a Roth option for the employee deferral portion — you can designate some or all of the $23,500 employee deferral as Roth (after-tax, with tax-free growth and withdrawals). The employer contribution portion is always pre-tax. This dual structure allows sophisticated tax planning: contribute to the Roth side in low-income years and to the traditional side in high-income years. Under SECURE 2.0 Section 604, employer contributions can also be designated as Roth beginning in 2023, but this is optional and not all plan providers support it yet.

The Solo 401(k) also permits loans from the plan (up to $50,000 or 50% of the vested balance, whichever is less) and hardship withdrawals. It has no income phase-outs — high-income earners can contribute the full amount regardless of MAGI. The plan must be established by 31 December of the tax year (not the filing deadline), and employee deferrals must be made by 31 December. Employer contributions can be made up to the return filing deadline, including extensions.

Solo 401(k) allows up to $23,500 employee deferral + 25% of net SE income as employer contribution, totaling up to $69,000 for 2026. Enhanced catch-up of $11,250 for ages 60-63 under SECURE 2.0. (IRC §402(g); IRC §415(c); IRC §401(c)(2); SECURE 2.0 §109)

SEP-IRA vs SIMPLE IRA: simpler alternatives with different trade-offs

The Simplified Employee Pension IRA (SEP-IRA) under IRC Section 408(k) allows employer-only contributions of up to 25% of net self-employment income, with a maximum of $69,000 for 2026. There is no employee deferral component — all contributions are employer contributions. For a sole proprietor, "net self-employment income" means Schedule C net profit minus 50% of SE tax (this adjustment is often overlooked, resulting in overcalculation of the allowable contribution). The effective maximum contribution rate is approximately 20% of net Schedule C profit (because the 50% SE tax deduction reduces the compensation base).

The SEP-IRA's primary advantage is simplicity. There is no plan document to file, no annual Form 5500 reporting requirement (unless the plan has substantial assets), and the plan can be established as late as the return filing deadline including extensions — meaning you can set up a SEP-IRA in October 2027 and make a deductible contribution for the 2026 tax year. This is the only major retirement plan that can be established and funded retroactively. The downside is the absence of employee deferrals: you cannot contribute the first $23,500 of earnings (as you would with a Solo 401(k)), and there is no Roth option.

The Savings Incentive Match Plan for Employees (SIMPLE IRA) under IRC Section 408(p) is designed for businesses with 100 or fewer employees. The employee deferral limit for 2026 is $16,500 (lower than the 401(k) limit of $23,500), with a catch-up of $3,500 for ages 50+. The employer must either match employee contributions dollar-for-dollar up to 3% of compensation or make a flat 2% non-elective contribution for all eligible employees. The SIMPLE IRA is less advantageous than a Solo 401(k) for sole proprietors because of the lower deferral limit and mandatory employer contributions. It is primarily useful for small businesses with employees where the administrative burden of a 401(k) is prohibitive.

A critical timing rule: you cannot maintain a SEP-IRA and a SIMPLE IRA in the same year. You can maintain a SEP-IRA and a Solo 401(k) simultaneously, but the total employer contributions across all plans are subject to the Section 415(c) annual additions limit. In practice, most sole proprietors choose either the Solo 401(k) (highest contributions, Roth option) or the SEP-IRA (simplest administration, retroactive establishment).

SEP-IRA: employer contributions only, up to 25% of net SE income ($69,000 max). Can be established by the return deadline. SIMPLE IRA: lower deferral limits ($16,500), suitable for small employers. (IRC §408(k); IRC §408(p); IRC §415(c))

Traditional and Roth IRAs, HSAs, and the MAGI phase-out traps

In addition to self-employment-specific plans, every self-employed individual can contribute to a Traditional or Roth IRA under IRC Section 408 and Section 408A. The 2026 contribution limit is $7,000, plus a $1,000 catch-up for ages 50 and older ($8,000 total). IRA contributions are in addition to Solo 401(k) or SEP-IRA contributions — they are under separate code sections with separate limits.

The deductibility of Traditional IRA contributions depends on whether you are covered by another retirement plan. If you maintain a Solo 401(k) or SEP-IRA, your Traditional IRA deduction begins to phase out at $79,000 MAGI (single) or $126,000 MAGI (MFJ, if the contributing spouse is the one covered). Above $89,000 (single) or $136,000 (MFJ), the deduction is fully phased out. You can still make a non-deductible Traditional IRA contribution and convert it to a Roth IRA (the "backdoor Roth" strategy), but beware of the pro-rata rule under IRC Section 408(d)(2) if you have existing pre-tax IRA balances — the conversion will be partially taxable based on the ratio of pre-tax to after-tax IRA assets.

Roth IRA contributions phase out at $150,000-$165,000 MAGI (single) or $236,000-$246,000 MAGI (MFJ) for 2026. Above these thresholds, direct Roth contributions are not permitted, but the backdoor Roth conversion remains available (Congress has considered restricting it but has not done so as of 2026).

The Health Savings Account (HSA) under IRC Section 223 is technically not a retirement account, but it functions as one. If you are enrolled in a high-deductible health plan (HDHP), you can contribute $4,300 (self-only) or $8,550 (family) for 2026, plus $1,000 catch-up if 55+. HSA contributions are deductible above-the-line (reducing AGI), growth is tax-free, and withdrawals for qualified medical expenses are tax-free — triple tax benefit. After age 65, HSA withdrawals for any purpose are taxed as ordinary income (like a Traditional IRA) but without penalty. For self-employed individuals, the HSA is an additional layer of tax-advantaged savings on top of the Solo 401(k) and IRA.

IRA contributions ($7,000 + $1,000 catch-up) are in addition to Solo 401(k)/SEP. Traditional IRA deductibility phases out if covered by another plan. HSA provides triple tax benefit for those with high-deductible health plans. (IRC §408; IRC §408A; IRC §408(d)(2); IRC §223)

Cash balance plans, Roth conversion ladders, and advanced strategies for high earners

For self-employed individuals with consistently high income ($300,000+), a defined benefit plan or cash balance plan offers the ability to shelter far more than the $69,000 Solo 401(k) limit. Cash balance plans are a type of defined benefit plan that express benefits as a hypothetical account balance rather than a monthly pension. The contribution limits are actuarially determined based on the participant's age, compensation, and years to retirement. For a 55-year-old with $300,000 in SE income, the annual contribution to a cash balance plan can exceed $200,000 — fully tax-deductible. Combined with a Solo 401(k), total tax-advantaged contributions can approach $270,000 per year.

Cash balance plans require an enrolled actuary to design and certify the plan, annual Form 5500 filings, and PBGC premiums (though sole proprietor plans may be exempt from PBGC coverage). The administrative cost is typically $2,000-$5,000 per year — significant, but modest compared to the tax savings. The commitment is also significant: defined benefit plans require consistent contributions, and underfunding can result in excise taxes. These plans are best suited for high-income professionals with stable, predictable SE income.

Roth conversion ladders are a strategy for early retirees or those with variable SE income. In low-income years (business downturn, sabbatical, early retirement), convert Traditional IRA or 401(k) funds to a Roth IRA, paying tax at a lower marginal rate. The converted funds are accessible without penalty after a 5-year holding period (per conversion). By converting systematically during low-income years, you build a pool of tax-free Roth funds for retirement while paying less tax than you would have if you waited until Required Minimum Distributions forced withdrawals at potentially higher rates.

For self-employed individuals planning retirement, the order of operations matters. First, maximise the Solo 401(k) (or SEP-IRA), which reduces taxable income dollar-for-dollar. Second, fund an HSA if eligible (triple tax benefit). Third, contribute to a Roth IRA (or backdoor Roth) for tax-free growth. Fourth, consider a cash balance plan if income exceeds $300,000 and is stable. Finally, invest in taxable brokerage accounts for amounts above all tax-advantaged limits. Each layer builds on the previous one to maximise long-term after-tax wealth.

Cash balance plans allow contributions exceeding $200,000/year for older, high-income earners. Roth conversion ladders exploit low-income years to convert pre-tax funds at reduced rates. (IRC §401(a)(17); IRC §415(b); IRC §408A(d)(3)(D); IRC §4980)

Action steps

1
Choose the right plan: Solo 401(k) for maximum flexibility, SEP-IRA for simplicity
If you have no common-law employees (a spouse is permitted), the Solo 401(k) offers the highest contribution limits and a Roth option. Open a Solo 401(k) by 31 December of the tax year to make employee deferrals for that year. If you missed the December deadline, a SEP-IRA can be opened and funded by the return filing deadline including extensions. If you have employees, compare the SIMPLE IRA (lower deferral limits but simpler) against a traditional 401(k) (higher limits but more administration).
2
Calculate your maximum contribution using net SE income
Your contribution is based on net self-employment income, defined as Schedule C net profit minus 50% of self-employment tax. For a Solo 401(k): employee deferral (up to $23,500) plus employer contribution (25% of net SE income). For a SEP-IRA: 25% of net SE income (effective rate approximately 20% of Schedule C net profit). Use IRS Publication 560 Worksheet or tax software to compute the exact maximum. Do not guess — overcontributions trigger a 6% excise tax under Section 4973.
3
Fund the plan before deadlines and make the right election
Solo 401(k) employee deferrals must be made by 31 December. Employer contributions can be made by the return deadline including extensions (typically 15 October if you extend). SEP-IRA contributions can be made by the return deadline including extensions. IRA contributions are due by 15 April (no extensions). Elect traditional (pre-tax) contributions in high-income years and Roth contributions in low-income years. Contribute early in the year rather than at the deadline to capture additional investment growth.
4
Max out your HSA if enrolled in a qualifying HDHP
If you have a high-deductible health plan, contribute the maximum HSA amount ($4,300 self-only / $8,550 family for 2026, plus $1,000 if 55+). Self-employed individuals deduct HSA contributions on Schedule 1 Line 13 (above the line). Pay medical expenses out of pocket if possible and let HSA funds grow tax-free. After age 65, the HSA functions as a second Traditional IRA with penalty-free withdrawals for any purpose.
5
Consider a backdoor Roth IRA if above income phase-outs
If your MAGI exceeds the Roth IRA contribution limits ($165,000 single / $246,000 MFJ for 2026), contribute to a non-deductible Traditional IRA and immediately convert to a Roth IRA. This is the backdoor Roth strategy. Ensure you have no existing pre-tax IRA balances (including SEP-IRAs and SIMPLE IRAs) to avoid the pro-rata taxation rule. If you have existing pre-tax IRA balances, consider rolling them into your Solo 401(k) first to isolate the after-tax IRA contribution.
6
Evaluate a cash balance plan if your SE income consistently exceeds $300,000
A cash balance plan allows contributions far above the Solo 401(k) limit, particularly for those over age 50. Consult a third-party administrator who specialises in defined benefit plans for sole proprietors. The setup and annual administration costs ($2,000-$5,000) are themselves tax-deductible business expenses. Ensure your income is stable enough to meet the contribution commitment — defined benefit plans have mandatory funding requirements that can be painful in a down year.

State variance

Iowa

Iowa allows a state income tax deduction for contributions to retirement plans (including Solo 401(k) and SEP-IRA) that follows the federal deduction. Iowa's flat state income tax rate of 3.9% (2026) means each dollar of retirement contribution saves an additional 3.9 cents at the state level.

California

California conforms to federal retirement plan contribution limits and deductions. California's top marginal state income tax rate of 13.3% makes tax-deferred retirement contributions particularly valuable — a $69,000 Solo 401(k) contribution saves over $9,100 in state income tax alone for top-bracket earners.

Texas

Texas has no state income tax, so retirement plan contributions provide federal tax savings only. For Texas residents, the decision between Roth (after-tax) and traditional (pre-tax) contributions depends entirely on expected federal tax rates in retirement versus the current year.

Worked example

Tom Wilson, a Cedar Rapids, IA-based Self-employed farmer approaching retirement, in 2026:

Tom, age 58, operates a family farm as a sole proprietor. His Schedule F net farm income is $70,000. He has no employees (seasonal help is hired through an ag services company). His wife Susan works part-time as a substitute teacher earning $15,000 in W-2 wages. They file married filing jointly. Tom wants to maximise retirement savings in his final working years.

Financial calculation for worked example:

Tom's self-employment income:
  Schedule F net farm income: $70,000
  SE tax: $70,000 × 92.35% × 15.3% = $9,888
  50% SE tax deduction: $4,944
  Net SE income for plan purposes: $70,000 − $4,944 = $65,056

  Plan comparison:

  Option 1 — Solo 401(k):
  Employee deferral: $23,500
  Catch-up (age 50+): $7,500
  Total employee side: $31,000
  Employer contribution: 25% × $65,056 = $16,264
  Total Solo 401(k): $31,000 + $16,264 = $47,264
  (Under $69,000 annual additions limit ✓)

  Option 2 — SEP-IRA:
  Employer-only: 25% × $65,056 = $16,264
  No employee deferral, no catch-up
  Total SEP-IRA: $16,264

  Option 3 — Solo 401(k) + IRA + HSA:
  Solo 401(k): $47,264
  Traditional IRA (Susan): $7,000 + $1,000 catch-up (if Susan is 50+) = $7,000 (Susan is 52)
  → $8,000 (IRA deductibility: Tom is covered by Solo 401(k), so his IRA deduction phases out.
  For the non-covered spouse (Susan), deduction phases out at $236,000-$246,000 MFJ →
  their AGI of ~$80,000 is well below → Susan's $8,000 IRA is fully deductible)
  Tom's IRA: non-deductible (covered by plan, AGI irrelevant at his income level, but he can
  contribute $8,000 non-deductible and do a backdoor Roth conversion)
  HSA (if HDHP): $8,550 family + $1,000 catch-up (Tom is 58, qualifies) = $9,550
  Total tax-advantaged: $47,264 + $8,000 (Susan IRA) + $8,000 (Tom backdoor Roth) + $9,550 (HSA) = $72,814

  Tax impact of Option 3:
  Combined income: $70,000 (Tom) + $15,000 (Susan) = $85,000
  Less: 50% SE tax: $4,944
  Less: Solo 401(k) employee deferral: $23,500 (reduces SE income for tax but not for SE tax itself —
  note: 401(k) deferrals reduce income tax but NOT self-employment tax)
  Correction: employee deferrals from a Solo 401(k) reduce income for income tax purposes
  but net SE earnings for SE tax are calculated before the deferral.
  Less: Solo 401(k) employer contribution: $16,264 (deductible on Schedule 1)
  Less: Susan IRA: $8,000
  Less: HSA: $9,550
  AGI: $85,000 − $4,944 − $16,264 − $8,000 − $9,550 = $46,242
  (Employee deferral reduces taxable income but is not an above-the-line deduction in the
  same way — it is excluded from income via W-2 box 12 for employees, but for SE individuals
  it reduces the income reported. For simplicity: treated as reducing income.)
  Effective AGI after all deductions: approximately $46,242 − $23,500 = $22,742

  Standard deduction (MFJ): $32,200
  Taxable income before QBI: $22,742 − $32,200 = negative → $0

  Tom and Susan owe $0 in federal income tax.
  SE tax: $9,888 (this is unavoidable — SE tax is calculated on net farm income before
  retirement plan deductions)
  50% SE tax deduction: $4,944 (already applied above)

  Total federal tax: $9,888 (SE tax only)
  Without retirement contributions:
  AGI: $85,000 − $4,944 = $80,056
  Standard deduction: $32,200
  Taxable income: $47,856
  QBI: 20% × $70,000 = $14,000, limited to 20% × $47,856 = $9,571
  Final taxable income: $47,856 − $9,571 = $38,285
  Tax: 10% × $23,850 + 12% × $14,435 = $2,385 + $1,732 = $4,117
  Total: $4,117 + $9,888 = $14,005

  Tax saved by retirement contributions: $14,005 − $9,888 = $4,117 federal income tax
  Plus Iowa state tax saved: approximately $46,000 in deductions × 3.9% = $1,794
  Total current-year tax savings: $5,911
  Total sheltered from taxation: $72,814

  At age 58, with 7-9 years until retirement at 65-67, these annual contributions of $47,264+
  (Solo 401(k) alone) accumulate to over $400,000 in additional retirement assets assuming
  6% annual growth — plus tax-deferred compounding on the full contribution amount.

Frequently asked questions

What happens if I miss the April 15 tax deadline?+

If you owe tax, the IRS charges two separate penalties: failure to file (5% of unpaid tax per month, max 25% under IRC §6651(a)(1)) and failure to pay (0.5% per month, max 25%). File Form 4868 for an automatic 6-month extension — but the extension only extends the FILING deadline, not the PAYMENT deadline. Interest accrues from April 15 regardless. If you have a clean 3-year history, you may qualify for First Time Abatement (FTA) to waive the failure-to-file penalty.

Do I need a CPA or can I file my own taxes?+

Most self-employed people with straightforward Schedule C income can file using tax software (TurboTax, FreeTaxUSA, TaxAct). Consider a CPA or Enrolled Agent (EA) if you have: an S-Corp election, multi-state filing, rental property with cost segregation, your first year of self-employment (to set up correctly), or an IRS notice. EAs are federally licensed and often less expensive than CPAs. The IRS Volunteer Income Tax Assistance (VITA) program offers free help for incomes under $67,000.

How do quarterly estimated tax payments work?+

Self-employed people must pay estimated tax quarterly (April 15, June 15, September 15, January 15) if they expect to owe $1,000 or more. The safe harbor under IRC §6654 is paying at least 100% of prior-year tax (110% if AGI exceeded $150,000). Use Form 1040-ES or pay via IRS Direct Pay or EFTPS. Missing payments triggers an underpayment penalty calculated per quarter — even if you pay everything at filing time.

Can I have both a Solo 401(k) and a SEP-IRA?+

Yes, but there is rarely a reason to do so. The total employer contributions across all plans are subject to the single Section 415(c) annual additions limit ($69,000 for 2026). If you contribute the maximum to a Solo 401(k), there is no room for additional SEP-IRA contributions. The common scenario where both coexist is when a self-employed individual establishes a Solo 401(k) mid-year and had previously made SEP-IRA contributions for that year. In that case, the total employer contributions across both plans cannot exceed the limit.

I missed the December 31 deadline to establish a Solo 401(k). What are my options?+

If you did not establish a Solo 401(k) by 31 December, you cannot make employee deferrals for that tax year. However, you can still establish and fund a SEP-IRA by the return filing deadline including extensions (typically 15 October). The SEP-IRA allows employer contributions of up to 25% of net SE income. For the following year, establish the Solo 401(k) before 31 December to capture the full employee deferral.

What is the enhanced catch-up contribution under SECURE 2.0?+

SECURE 2.0 Section 109 provides an increased catch-up contribution for participants aged 60-63 in 401(k), 403(b), and governmental 457(b) plans. For 2026, the enhanced catch-up is $11,250 (compared to the standard $7,500 catch-up for ages 50+). This means a 61-year-old with a Solo 401(k) can defer $23,500 + $11,250 = $34,750 on the employee side, plus the employer contribution. The enhanced catch-up reverts to the standard catch-up at age 64.

Does contributing to a retirement plan reduce my self-employment tax?+

No. Self-employment tax is calculated on net SE earnings (Schedule C or Schedule F net income × 92.35%) before any retirement plan deductions. Solo 401(k) deferrals, SEP-IRA contributions, and other retirement plan deductions reduce your income tax and AGI but do not reduce the SE tax base. The only deduction that reduces the SE tax base is the 50% SE tax deduction itself, which is built into the calculation. This means the SE tax savings from retirement contributions is zero — the savings come entirely from reduced income tax.

Last reviewed: June 1, 2026

Retirement Planning

Key mechanics

Solo 401(k): the most powerful option for self-employed individuals without employees

SEP-IRA vs SIMPLE IRA: simpler alternatives with different trade-offs

Traditional and Roth IRAs, HSAs, and the MAGI phase-out traps

Cash balance plans, Roth conversion ladders, and advanced strategies for high earners

Action steps

Choose the right plan: Solo 401(k) for maximum flexibility, SEP-IRA for simplicity

Calculate your maximum contribution using net SE income

Fund the plan before deadlines and make the right election

Max out your HSA if enrolled in a qualifying HDHP

Consider a backdoor Roth IRA if above income phase-outs

Evaluate a cash balance plan if your SE income consistently exceeds $300,000

State variance

Frequently asked questions