Do employee deferrals across jobs share a limit?

Yes. The elective deferral limit is across all 401(k)/403(b) plans. Employer contributions are separate per business.

Is the 25% rule on net profit?

It’s 25% of adjusted compensation (net × 92.35%) for self-employed.

Yes, IRS updates deferral, catch-up, and overall limits annually. Update inputs accordingly.

Does this handle multiple entities?

No. It’s a single-entity, simplified view.

No. It’s a planning estimate; consult a tax professional for specifics.

finance calculator

Solo 401(k) Contribution Calculator

Estimate maximum solo 401(k) employee and employer contributions based on net self-employment income.

Results

Compensation for employer calc: $73,880
Employer contribution: $18,470
Employee contribution (incl. catch-up): $23,000
Total contribution: $41,470

How to use this calculator

Enter net self-employment earnings.
Enter your planned employee deferral (up to the annual limit) and age to apply catch-up if 50+.
Review employer contribution, employee (incl. catch-up), and total contributions.

Inputs explained

Net earnings: Net profit from self-employment.
Employee deferral: Elective deferral up to the annual IRS limit.
Catch-up: Additional deferral allowed at age 50+ (if you’re 50 or older).

How it works

Compensation for employer portion = Net earnings × 92.35% (SE tax adjustment).

Employer contribution = 25% of that adjusted comp (capped by plan limits).

Employee deferral up to annual limit plus catch-up if age 50+. Total capped at plan max.

Formula

Comp for employer = Net earnings × 0.9235
Employer = Comp × 25%
Employee = Deferral + Catch-up (if 50+)
Total capped at plan limit

When to use it

Planning solo 401(k) contributions for freelancers/contractors.
Checking how much employer portion you can add on top of the deferral.
Comparing total contribution room at different income levels.

Tips & cautions

Employer contribution uses adjusted compensation (net × 92.35%) for self-employed.
Annual plan limits change; update employee deferral and plan max as needed.
If you participate in another 401(k), employee deferrals across plans share the same limit; employer portions differ.
Simplified; does not include overall plan maximum updates or multiple business entities.
Assumes plan limits (e.g., $23k deferral, $7.5k catch-up, $69k overall) — update annually.
Not tax advice; consult a professional for specifics.

Worked examples

$80k net, age 35, full deferral

Comp ≈ $73,880
Employer ≈ $18,470
Employee = $23,000
Total ≈ $41,470 (capped by plan max if applicable)

$120k net, age 52, full deferral + catch-up

Comp ≈ $110,820
Employer ≈ $27,705
Employee = $23,000 + $7,500 = $30,500
Total ≈ $58,205 (ensure within plan max)

Deep dive

Estimate solo 401(k) contributions by entering net self-employment income, deferral amount, age, and catch-up.

See employee, employer, and total contribution limits for freelancers/contractors.

FAQs

Do employee deferrals across jobs share a limit?: Yes. The elective deferral limit is across all 401(k)/403(b) plans. Employer contributions are separate per business.
Is the 25% rule on net profit?: It’s 25% of adjusted compensation (net × 92.35%) for self-employed.
Are limits indexed?: Yes, IRS updates deferral, catch-up, and overall limits annually. Update inputs accordingly.
Does this handle multiple entities?: No. It’s a single-entity, simplified view.
Is this tax advice?: No. It’s a planning estimate; consult a tax professional for specifics.

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Simplified solo 401(k) estimate. Does not cover all IRS nuances or multi-plan interactions. Confirm limits and rules with a tax/retirement professional.