Introduction to SEP IRA contribution limits
A SEP IRA lets a business make employer-funded retirement contributions for an owner and eligible employees. Its administration is relatively simple, but the contribution calculation is not always intuitive. A sole proprietor cannot normally multiply Schedule C profit by 25% and deposit that amount. The IRS first reduces self-employment profit by one-half of self-employment tax and then converts the stated plan percentage to a lower rate.
This calculator estimates that adjustment for Schedule C profit, calculates a contribution based on owner W-2 compensation, and applies editable compensation and annual-dollar limits. It also estimates the cost of applying the same plan percentage to eligible employee payroll. The default figures are intended for 2026 planning: a $72,000 annual additions limit, a $360,000 compensation cap, and a $184,500 Social Security wage base. Confirm current figures before funding an account.
How to use the SEP IRA contribution fields
Enter net self-employment income from Schedule C before deducting the ownerâs SEP contribution. If the business pays you W-2 wages, enter those separately because W-2 compensation uses the stated employer rate rather than the reduced self-employed rate. Do not treat an S corporation distribution as self-employment income or W-2 compensation merely to increase retirement-plan room.
Participant age does not affect the SEP result because a SEP IRA has no catch-up contribution. It is used only for the Solo 401(k) comparison. Eligible employee payroll is also optional, but it matters when judging affordability: a SEP generally requires the same contribution percentage for every eligible participant, even though each personâs dollar contribution can differ with compensation.
The employer contribution rate can range from 0% through 25%. The compensation cap, annual additions limit, and Social Security wage base are editable so the calculator can model another tax year. The optional Solo 401(k) deferral supplies a rough comparison rather than a complete plan-design analysis. After reviewing the entries, select Calculate SEP IRA Contribution. Read the result as an estimated ceiling, not a required deposit.
The SEP IRA formulas for a self-employed owner
The calculation begins with self-employment tax. In this simplified model, 92.35% of net profit is subject to the 2.9% Medicare portion. The 12.4% Social Security portion applies only up to the available wage base. Existing W-2 wages reduce the unused Social Security wage base:
Here, P represents Schedule C profit and W represents the remaining Social Security wage base. The calculator then deducts one-half of self-employment tax to estimate adjusted net earnings:
A stated plan rate must be reduced because a self-employed ownerâs contribution is determined from earnings that are themselves reduced by the contribution. Dividing the stated rate by one plus that rate resolves the circular calculation. At the maximum 25% plan rate, the reduced rate is 20%:
The reduced rate applies to adjusted self-employment earnings, while the full stated rate applies to qualifying owner W-2 compensation. The combined compensation base is restricted by the compensation cap, and the final contribution cannot exceed the annual additions limit:
In that expression, C is eligible owner W-2 compensation and L415 is the annual additions limit. The calculator proportionally trims the combined self-employment and W-2 bases if they exceed the entered compensation cap.
Worked example: $120,000 of consulting profit
Suppose a sole proprietor reports $120,000 of Schedule C profit, has no owner W-2 wages, and chooses the maximum 25% plan rate. The self-employment tax base is $110,820, which is 92.35% of the profit. Because that amount is below the 2026 wage base, both Social Security and Medicare rates apply. Estimated self-employment tax is $16,955.46, and one-half of it is $8,477.73.
Subtracting that deduction leaves $111,522.27 of adjusted net earnings. The 25% stated plan rate becomes a 20% reduced rate, producing an estimated contribution of $22,304.45. The amount is below both the $360,000 compensation cap and the $72,000 annual limit, so neither ceiling reduces it. The contribution equals about 18.59% of the original Schedule C profit, illustrating why multiplying profit directly by 25% would overstate the permitted amount.
Interpreting the SEP IRA result and employee cost
The headline result is the estimated maximum employer contribution for the owner under the entered assumptions. A lower contribution is generally possible; SEP plans do not require an owner to deposit the maximum every year. If the annual-dollar or compensation ceiling controls the answer, the result identifies that constraint. If neither ceiling binds, adjusted earnings and the selected contribution rate control it.
When employee payroll is entered, the calculator multiplies that aggregate payroll by the stated plan rate. This is a budgeting estimate only. In an actual plan, compensation limits and eligibility tests apply separately to each employee. The employer should verify age, service, compensation, controlled-group, and plan-document rules before making deposits.
SEP IRA and Solo 401(k) differences
A SEP IRA accepts employer contributions only. A Solo 401(k) can combine an employer profit-sharing contribution with an employee elective deferral, which often creates more contribution room at moderate income. Age-based 401(k) catch-up contributions may increase that difference, while SEP IRAs provide no catch-up. However, a Solo 401(k) is generally intended for an owner-only business and a spouse, not a business with eligible common-law employees.
The comparison shown by this calculator is deliberately narrow. It uses the SEP-style employer amount, the entered employee deferral, the annual additions limit, and the applicable 2026 catch-up assumption. It does not coordinate another employerâs plan, Roth treatment, nondiscrimination testing, controlled businesses, or every deadline rule.
Limitations of this SEP IRA estimate
The estimate assumes nonnegative income and applies a simplified Schedule SE calculation. It does not calculate the 0.9% Additional Medicare Tax, although that surtax is not included in the deductible half of self-employment tax. It also does not model partnership guaranteed payments, multiple Schedule C businesses, plan aggregation, elective deferrals made through another employer, or the special deductions that can arise in unusual entity structures.
Tax limits change over time, and plan eligibility can be more consequential than the arithmetic. Use final bookkeeping figures, check the applicable version of IRS Publication 560, and ask the plan custodian or a qualified tax professional to review the contribution before depositing it. An excess left uncorrected can trigger excise taxes, while an omitted employee contribution can require correction under the planâs terms.
Funding a SEP IRA after calculating the ceiling
A SEP can generally be established and funded by the business return deadline, including a valid extension. That flexibility lets an owner wait for final profit figures rather than relying on an early projection. Before funding, reconcile payroll and Schedule C records, confirm the tax-year limits, identify every eligible employee, and retain the calculation with the businessâs tax records.
SEP IRA contribution questions answered
Why is the effective SEP rate below 25%?
A self-employed owner subtracts one-half of self-employment tax and uses a reduced contribution rate. A 25% stated plan rate becomes 20% of adjusted net earnings, so the result is commonly around 18% to 20% of original Schedule C profit.
Does age increase a SEP IRA limit?
No. SEP IRAs do not have catch-up contributions. Age appears here only to make the Solo 401(k) comparison more informative.
Can I contribute less than the calculated amount?
Yes. The result is an estimated maximum under the entered assumptions. A business may generally choose a lower percentage or skip a contribution, subject to applying its selected percentage consistently to eligible participants.
When is the SEP contribution deadline?
The deadline generally follows the employerâs tax-return due date, including a valid extension. Confirm the deadline for the businessâs entity type and filing year.
Sources: Review the IRS guidance on calculating a self-employed retirement contribution, Publication 560, the IRS retirement-plan COLA limits, and the Social Security Administrationâs contribution and benefit base. Limits and individual circumstances should be verified for the filing year.