Carlos turned 62 this year and has been making catch-up retirement contributions since he turned 50 — he knew about the extra $8,000 a year that unlocks at 50. What he didn't know is that turning 60 unlocked a bigger one: $11,250 instead of $8,000, available only from age 60 through 63, worth an extra $3,250 a year he'd been leaving unclaimed since his birthday.
Two Different Catch-Up Amounts, Not One
Most people who know about catch-up contributions at all know the version that starts at 50: an extra $8,000 a year on top of the standard $24,500 employee deferral limit, available from 50 all the way through the rest of your working life. What's less known is that SECURE 2.0 created a second, larger tier specifically for ages 60 through 63 — $11,250 instead of $8,000 — before reverting back down to the standard $8,000 at 64. It's a four-year window, not a permanent increase, and it's easy to miss entirely if you set up your contribution amount once at 50 and never revisited it.
Carlos's Numbers, Net Self-Employment Income of $150,000
Carlos is a sole proprietor, not an S-Corp, so his contribution base isn't his raw $150,000 in net income — it's net income after deducting half his self-employment tax, per the IRS's own worksheet for this calculation:
Self-employment tax on $150,000: $150,000 × 92.35% = $138,525 in net earnings, taxed at 15.3% = $21,194. Half of that, deducted first: $10,597.
Contribution base: $150,000 − $10,597 = $139,403.
What a SEP IRA Would Allow
A SEP IRA is employer-only — there's no separate employee deferral bucket, and no catch-up contributions of any kind, regardless of age:
$139,403 × 20% = $27,881 maximum SEP IRA contribution for the year.
What Carlos's Solo 401(k) Actually Allows at 62
A Solo 401(k) lets Carlos contribute in two roles — as employee and as employer — plus the age-based catch-up:
- Employee deferral: $24,500 (flat, available to anyone with enough earnings to support it)
- Employer contribution: the same 20% formula as the SEP — $139,403 × 20% = $27,881
- Catch-up at age 62 (the 60–63 enhanced tier): $11,250
Total: $24,500 + $27,881 + $11,250 = $63,631.
The Gap, and the Part That's Easy to Miss
The overall Solo 401(k) advantage — $63,631 versus $27,881 — is $35,750 more, or 128% more retirement savings room at Carlos's income level. That part isn't age-specific; anyone in Carlos's income range gets most of that gap just from the employee deferral and employer-contribution structure.
The part that's specific to being 60 through 63: if Carlos were 59 instead of 62, his catch-up would be the standard $8,000, not $11,250 — his Solo 401(k) total would be $60,381 instead of $63,631. The four-year window from 60 to 63 is worth $3,250 more per year than the catch-up available at every other age from 50 onward. Miss it — by not adjusting your contribution once you turn 60, or by not knowing it exists — and that $3,250 a year of tax-advantaged room simply goes unused. It doesn't roll forward or get made up for later; at 64 the catch-up drops back to $8,000 permanently.
What $3,250 a Year Actually Adds Up To
At a 24% marginal federal rate (typical for Carlos's income if contributing pre-tax), the extra $3,250 in the 60-63 window saves about $780/year in federal income tax on top of the retirement savings itself — for each of the four years the enhanced catch-up is available, before it reverts. Contributed and invested rather than spent, that $3,250/year over just those four years, growing at a conservative 6%, adds a meaningfully larger cushion to retirement savings than treating the catch-up as a flat $8,000 the whole way through.
What This Doesn't Include
This assumes Carlos is a sole proprietor with no employees other than a spouse — a Solo 401(k) is only available in that structure, and adding a non-spouse employee takes it off the table. It's also pre-tax math; a Roth Solo 401(k) employee deferral (available up to the same $24,500, plus catch-up) is taxed differently and worth comparing separately based on expected tax rates now versus in retirement. And like every Solo 401(k), it has to be legally established by December 31 of the tax year to count for that year, even if funding happens later.
Check Your Own Age Window
If you're 60, 61, 62, or 63 this year and haven't specifically checked whether your contribution reflects the enhanced catch-up rather than the standard one, this is worth five minutes. Run your own net income and age through the Solo 401(k) vs SEP IRA Calculator to see your exact numbers — the calculator applies the correct catch-up tier automatically based on the age you enter.
Frequently Asked Questions
Why does the enhanced catch-up stop at 63 instead of continuing?
It's a specific SECURE 2.0 provision written into the statute as a four-year window (60 through 63), not an open-ended increase — Congress structured it this way rather than simply raising the standard 50+ catch-up permanently. At 64, the catch-up reverts to the standard $8,000 tier for the rest of your working life.
Does the enhanced catch-up apply to a SEP IRA too?
No — SEP IRAs have no catch-up contributions at any age, which is one of the two structural gaps (along with the lack of an employee deferral) that make Solo 401(k)s allow so much more contribution room at every age past 50, and especially in the 60-63 window.
What if Carlos already contributed the standard $8,000 catch-up this year before realizing he qualified for $11,250?
He can still contribute the additional $3,250 later in the same tax year, up to his plan's and the IRS's deadlines for the year — catch-up contributions aren't required to be made in one lump sum, and most Solo 401(k) providers allow multiple contributions throughout the year up to the combined limit.
Is the $11,250 catch-up in addition to the $24,500 employee deferral, or does it replace part of it?
Fully in addition. The catch-up sits on top of both the $24,500 employee deferral and the employer contribution — it isn't drawn from either, which is why Carlos's total ($63,631) is the simple sum of all three pieces rather than a blended or capped combination.
Does turning 64 mean Carlos loses money he already saved?
No — nothing about past contributions changes. What changes at 64 is only the catch-up amount available going forward, reverting from $11,250 to the standard $8,000. Money already contributed during the 60-63 window stays in the account and keeps growing under the plan's normal rules.