Section 105 vs Section 125 Plans:
What Employers Need to Know Before Choosing

Section 105 vs Section 125 is one of the most confused comparisons in employee benefits — partly because the two sections of the Internal Revenue Code sound interchangeable and partly because they are often used together. They are not the same thing, and choosing the wrong structure (or assuming one does what the other does) can cost an employer both compliance standing and real payroll tax savings. This guide breaks down exactly what each plan does, how they differ on funding, eligible expenses, and FICA savings, and how to decide which structure — or which combination — fits your company.

Section 105 vs Section 125: The Core Difference in One Sentence

Here is the distinction stripped to its essence: a Section 125 plan lets employees pay for benefits with their own pre-tax salary, while a Section 105 plan lets the employer reimburse employees for medical expenses tax-free. The first is funded by salary reduction; the second is funded by the employer. Almost every other difference between the two flows from that single fact about where the money comes from.

That funding distinction matters more than most employers realize, because it determines who saves on payroll taxes and how. When you understand which dollars are moving — the employee's pre-tax wages versus the employer's reimbursement budget — the rest of the comparison falls into place quickly. Keep that one sentence in mind as we work through the details, and the rest of this article will read as a series of consequences rather than a list of disconnected rules.

What a Section 125 Cafeteria Plan Actually Does

A Section 125 plan, commonly called a "cafeteria plan," allows employees to redirect a portion of their salary toward qualified benefits before federal income tax, Social Security tax, and Medicare tax are calculated. Because the deduction happens pre-tax, it lowers the employee's taxable wage base — and that is precisely what generates the payroll tax savings on both sides of the paycheck. Our complete guide to IRS Section 125 plans walks through the underlying mechanics in full.

The benefits that can run through a cafeteria plan include health, dental, and vision premiums, Health Savings Account (HSA) contributions, Flexible Spending Accounts (FSAs), dependent care assistance, and preventive healthcare programs. Federal rules require a written plan document before any of this can happen — at minimum a Premium Only Plan (POP) document. Without it, the deductions an employer thinks are pre-tax simply are not, which is one of the most common and expensive oversights we see in the field.

One important limit worth flagging: certain owners cannot participate in their own cafeteria plan. More-than-2% S corporation shareholders are blocked by IRC §1372, a trap covered in detail in our breakdown of Section 125 plans for S corp owners. This is one of the situations where a Section 105 arrangement sometimes becomes the more useful tool.

What a Section 105 Plan Actually Does

A Section 105 plan is an employer-funded medical reimbursement arrangement. Rather than letting employees divert their own salary, the employer sets aside dollars to reimburse employees for qualified medical expenses — and those reimbursements are excluded from the employee's taxable income. The best-known example is the Health Reimbursement Arrangement (HRA), including newer variants like the Individual Coverage HRA (ICHRA) and the Qualified Small Employer HRA (QSEHRA). Self-insured medical reimbursement plans (sometimes called MERPs) also live under Section 105.

The defining feature of a Section 105 plan is breadth. Because it is built to reimburse medical costs, it can cover a wider array of out-of-pocket expenses under IRC §213(d) — deductibles, copays, prescriptions, and other qualified medical costs — than a premium-focused cafeteria election typically does. That flexibility is the reason employers reach for Section 105 when the goal is to fully fund or supplement employees' medical spending with company dollars rather than to reduce the employees' own taxable wages.

Section 105 plans carry their own compliance regime. Self-insured arrangements are subject to the nondiscrimination rules in Section 105(h), which test whether the plan disproportionately favors highly compensated individuals. Those rules differ from cafeteria plan testing, a contrast we'll return to below and that connects to the broader topic of Section 125 nondiscrimination testing.

The Payroll Tax Question: Which Plan Saves on FICA?

This is where employers most often get the comparison wrong, so it deserves to be stated plainly. The FICA payroll tax savings most businesses are chasing come specifically from the Section 125 salary-reduction mechanism. When an employee's taxable wages drop because of a pre-tax election, both the employee and the employer stop paying the 7.65% FICA share on those dollars. That employer-side savings — averaging roughly $680 per employee per year in the plans we administer — is the engine behind nearly every "payroll tax savings" pitch in the market.

A pure Section 105 plan does not move that lever. Because it is funded with employer dollars rather than employee salary reduction, it does not lower the employee's Social Security and Medicare wage base, so it does not generate the same FICA savings. The reimbursements are still income-tax-free to the employee, which is a genuine and valuable benefit — but if an employer's primary objective is to cut the payroll tax line on their own quarterly 941, Section 105 alone will not deliver it. We've watched more than one business adopt a standalone HRA expecting FICA relief and come away puzzled when the payroll tax number didn't budge.

The honest takeaway: for payroll tax reduction specifically, Section 125 is the structure that does the work. Section 105 is the right tool when the goal is tax-free medical reimbursement funded by the company. The two solve different problems, and conflating them is the single most common mistake in this comparison. You can model the Section 125 side of the equation directly in our free payroll tax savings calculator.

Section 105 vs Section 125: A Side-by-Side Comparison

The fastest way to keep the two straight is to line up the features that actually drive a decision. Here is how Section 105 and Section 125 compare on the points that matter most to employers:

• Funding source: Section 125 is funded by employee pre-tax salary reduction; Section 105 is funded by employer dollars.
• Primary tax benefit: Section 125 reduces federal income tax and FICA for employees and FICA for employers; Section 105 provides income-tax-free medical reimbursements but does not cut the FICA wage base.
• Eligible expenses: Section 125 typically covers premiums, HSA/FSA contributions, and dependent care; Section 105 reimburses a broad range of §213(d) out-of-pocket medical costs.
• Required document: Section 125 requires a written cafeteria plan document (at minimum a POP); Section 105 requires its own written plan document, often an HRA or MERP document.
• Nondiscrimination testing: Section 125 runs eligibility, contributions-and-benefits, and a key-employee concentration test; self-insured Section 105 plans run the Section 105(h) eligibility and benefits tests.
• Best for: Section 125 is best for cutting payroll taxes through pre-tax elections; Section 105 is best for employers who want to fund or supplement employees' medical spending with company dollars.

A Worked Example: A 200-Employee Company

Numbers make the distinction concrete. Picture a company with 200 employees weighing how to structure pre-tax benefits and medical reimbursement. Using the Section 125 mechanism, each participating employee's pre-tax election lowers the wage base enough to generate roughly $680 in annual employer FICA savings. Across 200 employees, that's approximately $136,000 per year returned to the business — money that shows up directly on the quarterly payroll tax filing, starting as early as the next payroll cycle after the plan goes live.

Now suppose the same company instead set up only a Section 105 HRA and funded it with $1,000 per employee for out-of-pocket medical reimbursements. That arrangement delivers $200,000 of income-tax-free medical benefit to the workforce — a real perk that improves the benefits package — but it produces essentially zero employer FICA savings, because no employee salary was reduced. The company spent $200,000 and lowered its payroll tax bill by nothing.

The lesson is not that one plan is better than the other; it's that they're built for different outcomes. The employer who wants the $136,000 payroll tax reduction needs Section 125. The employer who wants to richly fund employees' medical costs reaches for Section 105. The employer who wants both designs them to work together — which is exactly what most sophisticated benefits programs do. Run your own headcount through the savings calculator to see the Section 125 figure for your business.

How the Two Plans Work Together

In practice, Section 105 and Section 125 are far more often partners than rivals. A common and powerful design uses a Section 125 cafeteria plan to let employees pay their share of premiums and fund HSAs or FSAs pre-tax — capturing the FICA savings — while a Section 105 HRA reimburses out-of-pocket medical costs the cafeteria elections don't reach. Employees get broader coverage; the employer gets the payroll tax reduction plus a richer benefits offering.

This layering is also where compliance gets interesting, because a single benefit can fall under both sets of rules and therefore both sets of nondiscrimination tests. An employer can't simply pick the friendlier test and ignore the other. Integrated programs need annual testing that accounts for Section 125's key-employee concentration test and Section 105(h)'s eligibility and benefits tests at the same time. This is precisely the kind of structural coordination that benefits from professional administration rather than a do-it-yourself spreadsheet — and it's part of the preventive healthcare benefits program we build for employers.

Which Plan Is Right for Your Business?

Start with your objective, because that determines the answer faster than any feature chart. If your primary goal is to reduce payroll taxes and put money back on your quarterly 941, you need a Section 125 cafeteria plan — that's the only structure of the two that lowers the FICA wage base. This is the path most of our clients are on, and it pairs naturally with the broader payroll tax savings strategies employers should be using in 2026.

If your goal is to give employees tax-free help with out-of-pocket medical costs — especially if you want to control exactly how much the company contributes — a Section 105 plan is the better fit. And if you want both the payroll tax reduction and the medical reimbursement flexibility, the right answer is a coordinated design that uses each section for what it does best. The wrong move is assuming a single plan accidentally covers both goals; it rarely does, and the gap usually surfaces at tax time or during an audit.

For most mid-sized employers — companies with 50 or more employees, which is where these plans pay off most clearly — the highest-value starting point is getting the Section 125 foundation right, then deciding whether a Section 105 layer adds enough value to justify the additional administration. That sequence captures the payroll tax savings first and builds from there.

Section 105 vs Section 125 — Frequently Asked Questions

Can an employer have both a Section 105 and a Section 125 plan?

Yes, and many employers do. The two sections of the Internal Revenue Code govern different mechanics and are frequently layered together. A Section 125 cafeteria plan lets employees pay their share of premiums and fund accounts with pre-tax salary, while a Section 105 plan lets the employer reimburse out-of-pocket medical expenses tax-free. They are complementary, not mutually exclusive — a well-designed benefits program often uses both at once.

Does a Section 105 plan reduce payroll taxes the same way a Section 125 plan does?

Not in the same way. The FICA payroll tax savings most employers are after come from the pre-tax salary reduction mechanism in Section 125 — when an employee's taxable wages drop, both the employee and the employer save the 7.65% FICA share on those dollars. A pure Section 105 plan is funded with employer dollars rather than employee salary reduction, so it does not lower the employee's Social Security and Medicare wage base. Section 105 reimbursements are still income-tax-free to the employee, but the payroll-tax savings engine is Section 125.

Is an HRA a Section 105 or a Section 125 plan?

A Health Reimbursement Arrangement (HRA) is a Section 105 plan. It is employer-funded and reimburses employees for qualified medical expenses on a tax-free basis. It cannot be funded by employee salary reduction — if it were, it would no longer be an HRA. This is the cleanest way to remember the distinction: employer money reimbursing medical bills is Section 105 territory, while employee pre-tax salary funding benefits is Section 125 territory.

What is the difference between Section 105(h) and Section 125 nondiscrimination testing?

Both prevent a plan from favoring highly compensated or key employees, but they apply different tests. Section 105(h) governs self-insured medical reimbursement plans and runs an eligibility test and a benefits test focused on highly compensated individuals. Section 125 testing adds a key-employee concentration test on top of eligibility and contributions-and-benefits testing. A benefit offered through both sections may have to satisfy both sets of rules, which is why integrated plans need careful annual testing.

Do small businesses need a Section 125 plan to offer pre-tax benefits?

Yes. Federal rules require a written Section 125 plan document — at minimum a Premium Only Plan (POP) — before any employee can pay for benefits with pre-tax dollars. Without that document in place, premium deductions are not legally pre-tax, even if payroll is processing them that way. Small businesses with 50 or more employees are exactly the group that captures the most measurable payroll tax savings once the document and plan are set up correctly.

For authoritative reference, the IRS maintains a plain-language overview of cafeteria plans in its FAQs on Section 125 cafeteria plans, and SHRM publishes a detailed employer toolkit on understanding Section 125 cafeteria plans. Both are worth bookmarking before you finalize a plan design.