Solo 401(k) Contribution Limits for Freelancers (2026): How Much Can You Really Put Away?

Published: June 19, 2026 · Reading time: 8 min

TL;DR: A solo 401(k) (also called an individual or one-participant 401(k)) lets a self-employed person contribute as both employee and employer — which is why it allows far more than an IRA. For 2026 the combined cap is $70,000 (under 50): a $23,500 employee deferral plus an employer profit-sharing contribution of up to 25% of net self-employment earnings. Add a $7,500 catch-up at age 50+ (cap rises to $77,500), or the $11,250 super catch-up at ages 60–63 (cap rises to $81,250). The employee deferral is a flat amount regardless of profit; the employer side scales with earnings. Plan must generally be open by December 31, but employer money can be funded up to your filing deadline plus extensions.

If you're a freelancer with strong profit and no employees, the solo 401(k) is usually the single most powerful tax shelter you have. It beats a SEP-IRA at most income levels because of one feature: you get to contribute as the employee and as the employer. Here's exactly how much that adds up to for 2026, and how the math actually works for a sole proprietor.

Why a Solo 401(k) Holds So Much: Two Hats

A traditional or Roth IRA caps you at a few thousand dollars. A solo 401(k) is bigger because you fill two roles in your own business:

1. As the employee, you make an elective deferral — up to $23,500 for 2026.
2. As the employer, your business makes a profit-sharing contribution — up to 25% of net self-employment earnings.

Stack both and the combined 2026 limit is $70,000 (under 50). That ceiling is the IRS Section 415(c) annual additions limit.

The 2026 Numbers at a Glance

The catch-up applies to the employee deferral side. The 60–63 "super catch-up" is a SECURE 2.0 feature that replaces the regular $7,500 catch-up only during those four ages.

These figures are indexed by the IRS each year — always confirm the current year's amounts before you contribute.

How the Employer Contribution Math Really Works

The employer side is "25% of compensation," but for a sole proprietor, compensation isn't your Schedule C number straight off the form. The IRS makes you back out two things:

1. Start with net profit from Schedule C Line 31.
2. Subtract the deductible half of self-employment tax.
3. Apply the contribution rate to that adjusted figure.

Because the contribution itself reduces the base it's calculated on, the effective employer rate for a sole proprietor lands at roughly 20% of adjusted net earnings rather than a flat 25%. You don't have to compute this by hand — every solo 401(k) provider and tax program runs the worksheet (IRS Publication 560 has the official one).

The employee deferral is far simpler: a flat up-to-$23,500, no percentage, as long as you earned at least that much.

Worked Example

Avery, a freelance consultant, age 42, net profit $120,000:

• Deductible half of SE tax ≈ $8,500 → adjusted net earnings ≈ $111,500.
• Employee deferral: $23,500 (the flat max).
• Employer profit-sharing: ≈ 20% × $111,500 ≈ $22,300.
• Total ≈ $45,800 — all of it reducing taxable income (traditional).

Notice Avery hasn't hit the $70,000 ceiling — that requires higher profit. The lesson: the flat $23,500 deferral is what makes the solo 401(k) so strong at moderate income, where a SEP-IRA (employer-only) would allow far less. See the full comparison in SEP-IRA vs Solo 401(k).

The Day-Job Coordination Trap

The $23,500 deferral limit is per person, not per plan. If you also defer into a 401(k) at a W-2 job, that eats into your $23,500 — you can't double up the deferral. This matters for anyone running a W-2 job plus 1099 side income.

The good news: the employer profit-sharing side is separate. Even if your day-job 401(k) uses up the full deferral, your business can still make its 25%-of-earnings employer contribution into the solo 401(k), subject to the per-plan $70,000 cap.

Roth vs. Traditional

Most solo 401(k) providers offer both flavors:

• Traditional — deductible now (an above-the-line adjustment on Schedule 1, not a Schedule C expense), taxed in retirement.
• Roth — after-tax now, tax-free later. Under SECURE 2.0, even employer contributions can be Roth if the plan allows.

Pick traditional if you're in a high bracket today and expect a lower one later; pick Roth if you expect higher future rates or want tax-free growth. Lower-income years may also unlock the Saver's Credit on the employee-deferral portion.

Deadlines That Trip People Up

• Open the plan by December 31 to make employee deferrals for that year. (SECURE 2.0 allows opening after year-end for employer-only contributions, up to your filing deadline.)
• Fund employer contributions up to your tax-filing deadline, including extensions — see Form 4868 extensions.
• The plan must be truly solo — you and a spouse only. Hiring a non-spouse employee can end its one-participant status.

The safe habit: open the account before year-end so both contribution types stay on the table, then finalize the dollar amounts when you know your final net profit.

How It Fits Your Bigger Tax Picture

A solo 401(k) is one of the strongest year-end tax moves for freelancers: it shelters income, can lower the AGI that drives the premium tax credit, and pairs with estimated-tax planning. Very high earners who've maxed it out can look at a defined benefit plan on top.

Frequently Asked Questions

What is the solo 401(k) contribution limit for 2026?

For 2026 the combined limit is $70,000 if you're under 50. That's made of two parts: an employee elective deferral of up to $23,500, plus an employer profit-sharing contribution of up to 25% of your net self-employment earnings. If you're 50 or older you can add a $7,500 catch-up (raising the combined cap to $77,500), and under SECURE 2.0 those aged 60–63 get a larger $11,250 catch-up (raising it to $81,250). The catch-up applies to the employee deferral side.

How is the employer (profit-sharing) contribution calculated for a sole proprietor?

It's "25% of compensation," but for a sole proprietor compensation means net earnings from self-employment — not Schedule C net profit as-is. You start with Schedule C Line 31 net profit, subtract the deductible half of self-employment tax, and the effective employer contribution works out to roughly 20% of that adjusted figure (the 25% applied to net-of-contribution earnings). In practice, plan providers and tax software run this calculation for you. The employee deferral is simpler: a flat dollar amount up to $23,500 regardless of profit, as long as you earned at least that much.

Can I contribute the full $23,500 deferral if I also have a job with a 401(k)?

The $23,500 employee deferral limit is per person, not per plan. If you defer into a 401(k) at a W-2 job, that uses up part (or all) of your $23,500, leaving less room in your solo 401(k) deferral. However, the employer profit-sharing side of your solo 401(k) is separate — your business can still make up to 25% of net earnings, independent of the day-job plan, subject to the per-plan $70,000 cap. So a moonlighter can often still contribute substantial employer money even when the deferral is maxed elsewhere.

When do I have to open and fund a solo 401(k)?

To make employee deferrals for a tax year, the plan generally must be established by December 31 of that year (SECURE 2.0 lets you open a plan after year-end for employer contributions only, up to your filing deadline). Funding deadlines are more generous: employer contributions can be made up to your tax-filing deadline including extensions, and employee deferrals shortly after year-end. The safe move is to open the account before December 31 so both contribution types stay available.

Should I choose a Roth or traditional solo 401(k)?

Most solo 401(k) plans offer both. Traditional contributions are deductible now and taxed in retirement; Roth contributions (employee deferral side, and now employer contributions too under SECURE 2.0 if the plan allows) are after-tax now and tax-free later. Traditional usually wins if you're in a high bracket today and expect a lower one in retirement; Roth wins if you expect higher future rates or want tax-free growth. Many freelancers split. The deduction for traditional contributions is an above-the-line adjustment, not a Schedule C expense.

Authoritative References

• IRS — One-Participant 401(k) Plans
• IRS — Retirement Topics: 401(k) and Profit-Sharing Plan Contribution Limits
• IRS — Publication 560, Retirement Plans for Small Business
• IRS — SECURE 2.0 Act Changes

Related reading: SEP-IRA vs Solo 401(k) · Backdoor Roth IRA for freelancers · Defined benefit plans for high earners · Year-end tax moves

Know Your Net Profit Before You Set Your Contribution

Your solo 401(k) limit is built on your Schedule C net profit — so the more deductions you capture, the cleaner that number is. CentSense scans every business receipt, tags it to the right Schedule C line, logs your mileage at $0.725/mile, and exports a CPA-ready CSV, so you walk into your retirement-contribution math with accurate net earnings instead of a guess. Free tier includes 10 AI scans per month; Solo is $5/month for unlimited scanning and mileage logging.

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This guide is general education for U.S. freelancers and Schedule C filers in 2026. It is not personalized tax or investment advice — contribution limits are indexed annually and your situation is unique, so confirm current figures and bring your plan to a CPA or financial advisor.