SEP IRA to Roth IRA Conversion: The Self-Employed Guide

For most working Americans, the Roth conversion golden window opens at retirement — when wages stop and Social Security hasn't started yet. Self-employed professionals get something better: a gradual wind-down. As a freelancer, consultant, or solo-practice owner cuts back their client load at 58, 62, or 65, their taxable income drops year by year. That's not just a natural transition — it's an engineered low-bracket window that can span a decade. The opportunity is to convert decades of SEP-IRA savings during that window at 12–22%, rather than paying 32% or more when RMDs force distributions starting at age 73 (or 75 for those born 1960 or later).

How a SEP-IRA converts to Roth: the mechanics

A SEP-IRA is a traditional IRA for tax purposes. The conversion mechanics are identical to a traditional IRA-to-Roth conversion:

• No income limit. Roth IRA contributions phase out at $153,000–$168,000 (single) and $242,000–$252,000 (MFJ) in 2026.¹ Roth conversions have no income limit — the backdoor was closed for contributions, not for conversions.
• No dollar cap on conversion. You can convert any amount from your SEP-IRA in a single year. The only constraint is the tax bill you're willing to absorb.
• No mandatory 20% withholding. A 401(k) rollover to Roth triggers automatic 20% withholding on a check payable to you. An IRA-to-Roth conversion does not — the custodian transfers the assets directly. You pay taxes separately, ideally from outside funds.
• 100% taxable — in most cases. All SEP-IRA contributions were deductible. There's no non-deductible basis in a SEP, so nearly the entire conversion amount is ordinary income. (If you also have traditional IRA accounts with Form 8606 basis, the pro-rata rule aggregates everything — more on this below.)
• Form 8606 required. You must file Form 8606 in the year of conversion to report the taxable amount and track your new Roth basis.

The tax cost: nearly 100% taxable, but that's the whole point

Because every dollar you contributed to your SEP-IRA was deducted from income, the IRS hasn't collected any tax on those funds yet. Converting $100,000 from a SEP-IRA adds $100,000 to your ordinary income for the year — the same as if you'd received $100,000 in consulting fees.

The question isn't whether you'll pay tax on that money. You will, one way or another — either when you convert or when you take distributions (including forced RMDs starting at 73 or 75). The question is which bracket you'll pay it in.

The self-employed wind-down window

Employed workers face a binary income transition: full salary, then retirement. Self-employed professionals face a gradient. A consultant might go from $350,000 in billable income at age 58, to $220,000 at 62, to $80,000 at 65, to zero at 68. Each step down in income is a step down in marginal bracket — and an opportunity to convert more at a lower rate.

For someone born in 1960 or later, the RMD clock doesn't start until age 75 (SECURE 2.0, § 107). That's a potential 10–15 year conversion runway from retirement to first mandatory distribution.

The extended deadline strategy: fund and convert across two tax years

SEP-IRA contributions for a given tax year can be made as late as your business tax return due date, including extensions. For most self-employed filers that's October 15 of the following year.² This creates a planning opportunity unavailable to W-2 employees:

1. Fund the 2026 SEP-IRA by October 15, 2027. Deduct the contribution on your 2026 return, reducing your 2026 taxable income.
2. Convert that balance to Roth in 2027. The conversion is taxable in 2027 — in a year when your income may be lower (further along the wind-down) and your bracket may have stepped down another notch.

This is legal and well-documented. The IRS allows SEP contributions after year-end precisely because self-employment income isn't finalized until the return is prepared.

Worked example: Gary, age 62, management consultant

Gary is a sole proprietor who has been funding a SEP-IRA for 20 years. He's accumulated $680,000 in the account — all pre-tax. He's now cutting his client load by about half each year. Here's his conversion plan:

Over 7 years, Gary converts $590,000 at an average effective rate of roughly 20%. His remaining $90,000 in the SEP-IRA generates modest RMDs starting at 75. Compare that to the no-conversion path: at 75, the full $680,000 (plus decades of compounding — call it $1.1M) forces annual RMDs of $48,000 or more, stacked on top of Social Security in the 24–32% bracket, with IRMAA Tier 2 surcharges adding another $600+ per month in Medicare premiums.

The pro-rata rule and why it matters

The IRS aggregates all your traditional IRAs — including SEP-IRAs — into a single pool for calculating the taxable percentage of any conversion.³ This matters if you've ever made non-deductible contributions to a traditional IRA and have Form 8606 basis tracked. If your only IRA is a SEP with all pre-tax contributions, there's no basis and no pro-rata complexity — the conversion is 100% taxable.

Where it gets complicated: if you also have a traditional IRA with $30,000 of non-deductible basis (tracked on Form 8606), and your total IRA balance is $680,000, then only $30,000/$680,000 = 4.4% of any conversion is tax-free. The self-employed 401(k) workaround below addresses this.

The solo 401(k) rollover: clearing the pro-rata pool

Self-employed professionals have an option that most employees don't: establishing a solo 401(k) (also called individual 401(k) or owner-only 401(k)) and rolling their pre-tax IRA balances into it. A solo 401(k) is a qualified plan — it is excluded from the pro-rata aggregation pool for IRA basis purposes.

Rolling your $680,000 SEP-IRA into a solo 401(k) removes it from the pool. If you then make a new non-deductible IRA contribution of $7,500 (2026 IRA limit) and immediately convert that $7,500 to Roth, the conversion is 100% tax-free because the Form 8606 pool now contains only the $7,500 of basis with no pre-tax balance to dilute it.

This is the backdoor Roth IRA strategy — and it works cleanly for self-employed professionals who can roll pre-tax IRA balances into a solo 401(k). Note: the solo 401(k) must be established and receive the rollover before year-end for the pro-rata calculation to exclude it.

SIMPLE IRA: different rules apply

If you sponsored or participated in a SIMPLE IRA plan rather than a SEP-IRA, the same conversion opportunity exists — but with one important restriction: the two-year rule.

Under IRC § 408(d)(3)(G) and § 72(t)(6), you cannot roll a SIMPLE IRA out of the plan (to a traditional IRA, Roth IRA, or any other plan) within the first two years of your initial participation in that SIMPLE plan.⁴ Distributions taken during this window are not eligible for rollover and incur a 25% early distribution penalty (not the standard 10%) if you're under 59½. After the two-year window closes, SIMPLE IRA funds can be converted to Roth on the same terms as any traditional IRA.

The 2026 SIMPLE IRA employee deferral limit is $17,000 for most plans; small employers (25 or fewer employees) may use $18,100 under SECURE 2.0 provisions.⁵ Catch-up contributions: $4,000 for ages 50–59 and 64+; $5,250 for ages 60–63 (SECURE 2.0 super-catch-up).

The SEP contribution limit for 2026

The 2026 SEP-IRA contribution limit is the lesser of $72,000 or 25% of compensation, with compensation capped at $360,000.⁶ For self-employed individuals, the effective contribution rate is approximately 20% of net self-employment earnings after the deduction for 50% of self-employment tax. This represents a meaningful pre-tax savings opportunity in active business years — and an equally meaningful conversion opportunity once income steps down.