SIMPLE IRA vs 401(k) — finding the crossover point

The SIMPLE IRA is genuinely well named. There's no plan document to maintain, no Form 5500, no nondiscrimination testing, and no meaningful admin fee. For a business with a handful of employees and an owner who isn't trying to save aggressively, it's often the correct answer, and I have no interest in upselling anyone out of it.

But the SIMPLE has a ceiling, and businesses grow through it quietly — usually two or three years before anyone notices.

What the SIMPLE actually requires

A SIMPLE IRA commits you to one of two employer contributions:

• A dollar-for-dollar match up to 3% of pay for employees who defer (reducible to 1% in two years out of five [VERIFY]), or
• A flat 2% nonelective contribution for every eligible employee, deferring or not.

Employees can defer up to $17,000 [VERIFY: 2026 SIMPLE limit], with a $4,000 [VERIFY: 2026] catch-up at 50+. SECURE 2.0 also added a wrinkle worth checking: employers with 25 or fewer employees get limits roughly 10% higher automatically, and larger SIMPLE sponsors can elect higher limits by paying a richer match [VERIFY: current higher-limit rules and figures].

Contributions vest immediately, land in each employee's own IRA, and there is essentially nothing to administer. That's the whole appeal.

Where the ceiling bites

Compare the maximum the owner can put away in each plan:

The deferral gap alone is $7,500 [VERIFY] a year. Add profit sharing — especially a new comparability design that legally skews employer dollars toward owners and older employees — and the 401(k) isn't playing the same sport. For a 50-year-old owner, catch-up differences widen the gap further [VERIFY: 2026 401(k) catch-up $8,000 vs SIMPLE catch-up $4,000].

There are quieter costs too. SIMPLE deferral participation makes a backdoor Roth messy, because SIMPLE balances count in the pro-rata calculation. Roth SIMPLE contributions exist on paper post-SECURE 2.0 but support remains spotty [VERIFY]. And the SIMPLE's infamous 2-year rule penalizes rollovers out of the plan within the participant's first two years at a brutal 25% [VERIFY], which complicates transitions if you don't plan them.

Finding your crossover point

Ignore headcount rules of thumb. The crossover is almost always about the owner's savings appetite. Run this arithmetic:

1. How much more do you want to save than the SIMPLE allows? If the answer is "$5,000," stay put. If it's "$25,000," keep reading.
2. What does the extra employer cost look like? A safe-harbor match (dollar-for-dollar on the first 3% plus 50 cents on the next 2% — max 4% of pay [VERIFY: basic safe-harbor formula]) versus the SIMPLE's 3% match is roughly one extra point of payroll for participating employees. On a $600,000 non-owner payroll with decent participation, maybe $4,000–6,000 a year.
3. What does administration cost? Small-plan bundled pricing commonly runs $2,000–4,000 a year plus per-participant fees [VERIFY: current market pricing]; a TPA-plus-recordkeeper arrangement somewhat more.
4. What's the tax value of the extra room? An owner in a combined 40% bracket who moves from $21,500 to $50,000+ of annual contributions is deferring tax on roughly $30,000 a year — worth about $12,000 annually.

When line 4 exceeds lines 2 and 3 combined — and for owners with real savings capacity it usually does, decisively — you've crossed over. The employer contribution isn't purely a cost either: it's deductible compensation, and some of it lands in your own account.

There's also a non-financial trigger: recruiting. A 401(k) reads as a real benefit to candidates in a way a SIMPLE doesn't, particularly once you're hiring against larger companies.

The mid-year switch is now allowed

For decades the rule was rigid: a SIMPLE had to run the full calendar year, so switching meant deciding by November and starting the 401(k) in January. SECURE 2.0 changed that — an employer can now terminate a SIMPLE mid-year if it's replaced with a safe-harbor 401(k), with the deferral limits prorated between the two plans for the year [VERIFY: mid-year replacement rules, effective 2024, and proration mechanics]. The rollover 2-year rule also got an exception for these plan-replacement transfers [VERIFY].

The practical playbook:

1. Model the plan design first (safe harbor type, match formula, profit sharing, eligibility) — this is where a TPA earns their fee.
2. Set a conversion date with clean payroll cutover; the notice requirements have specific timing [VERIFY: required notice period].
3. Communicate the why to employees — a richer match sells itself if anyone bothers to explain it.
4. Handle the old SIMPLE balances deliberately rather than leaving a graveyard of small IRAs behind.

The bottom line

Keep the SIMPLE while it still fits — it's a good plan wearing an honest name. But price the upgrade the right way: not "a 401(k) costs $3,000 and the SIMPLE is free," which is the framing that keeps owners stuck, but "what is the after-tax value of the contribution room I'm not using?" The day that number gets big, the SIMPLE stopped being simple — it started being expensive.