2026 Open Enrollment Checklist: What US HR Teams Must Finish Before Employees Choose Benefits

Why This Year’s Open Enrollment Leaves Less Room for Error

Every fall, HR teams run the same basic playbook: lock plan rates, update the numbers, tell employees what changed, watch the clock. Most years, that playbook survives on autopilot. This year it won’t, because the two biggest inputs HR teams build enrollment materials around, the ACA affordability threshold and the health FSA limit, are moving in ways that actually change what employees pay and what a benefits team needs to plan for.

The affordability percentage for 2027 plan years is 10.22%, up from 9.96% in 2026, and it’s the first time that number has ever crossed 10%. That’s not a rounding change; it directly resets how much you can charge a full-time employee for self-only coverage before you risk an employer mandate penalty. At the same time, the 2027 health FSA limit hasn’t been finalized by the IRS as of this writing, which means any enrollment guide, decision-support tool, or payroll system update built today around a projected number needs a second pass the moment the IRS makes it official, typically in October or November.

None of this changes what “open enrollment” fundamentally is. It changes how much slack you have to get the details right before employees start making decisions based on numbers your systems are showing them.

What Changes for the 2027 Plan Year?

The rate hasn’t moved on most of these, only the ceiling has, and the ceiling is what your enrollment materials, payroll system, and benefits platform all need updated before employees start electing.

The health FSA limit and 401(k) deferral limit below are the two figures still awaiting official IRS confirmation, expected in the agency’s fall revenue procedure.

One nuance worth flagging directly to employees during enrollment: the standard 401(k) catch-up contribution for employees turning 50 is $8,000 in 2026, but employees turning 60 to 63 get a separate, higher “super catch-up” of $11,250, a SECURE 2.0 provision that’s easy to miss because it doesn’t apply at the same age as the regular catch-up.

The 2026 Open Enrollment Checklist: What to Finish Before the Window Opens

Break this into four phases instead of one long list. Trying to do all of it in the final two weeks is the single most common reason enrollment periods get extended.

90 to 60 Days Out: Lock Plan Design and Rates

1. Finish carrier renewal negotiations and lock final rates. Payroll and your benefits administration platform both need final numbers loaded well before employees start electing, not the week enrollment opens.
2. Decide on any plan design changes (deductibles, HSA-eligible options, new voluntary benefits) and confirm each one is compliant with the 2027 HSA and ACA limits above before you announce it.
3. Update Summary Plan Descriptions and Summary of Benefits and Coverage (SBC) documents for every plan option being offered, these need to be current the moment enrollment materials go out.
4. Load confirmed 2027 contribution limits into payroll and your HRIS/benefits platform, and flag the FSA and 401(k) fields specifically for a second pass once the IRS issues its official fall numbers.
5. Build the side-by-side plan comparison employees will actually use to decide, not just a PDF of last year’s chart with new numbers swapped in.

30 Days Out: Notices, Communication, and System Testing

1. Distribute required notices: the updated SBC, the Medicare Part D creditable or non-creditable coverage notice (due before October 15 regardless of your own enrollment dates), a CHIP notice if you have employees in a state that offers premium assistance, and a WHCRA notice if applicable.
2. Build a communication calendar that names, for every message: the audience, the channel, who sends it, and the deadline it’s driving toward.
3. Train HR and frontline managers on the most likely employee questions before enrollment opens, so the same question doesn’t land in the HR inbox forty separate times during week one.
4. Run a full test enrollment end-to-end in your HRIS or benefits platform, from election through the carrier eligibility file, before a single real employee touches the live system.

During the Enrollment Window

1. Keep the window open at least 14 days, the ACA/cafeteria plan minimum; most employers run two to four weeks in practice.
2. Send reminders through at least two channels (email plus SMS, Slack, or a mailer for remote and frontline staff who don’t check a work inbox daily), timed at the halfway point and again 48 hours before close.
3. Track completion in real time and follow up individually with non-responders, instead of waiting for the deadline to pass and dealing with a wave of “I missed it” requests after the fact.
4. Route qualifying life events and late-enrollment requests through a separate, documented process. Don’t quietly extend the general deadline for everyone just to accommodate a handful of stragglers.

After Enrollment Closes

1. Audit every election against plan rules before the first payroll deduction posts. This is the cheapest point in the entire process to catch an error; it only gets more expensive from here.
2. Confirm carrier and TPA eligibility files reflect final elections. A mismatch here is what causes a claim to get denied in February for coverage the employee thought they had since January.
3. Send employees a confirmation statement showing exactly what they enrolled in and their new per-pay-period cost, before their first 2027 paycheck, not after.
4. Calendar the Q1 compliance deadlines this enrollment directly feeds into: Form 1095-C furnished to employees by January 31, and filed with the IRS by February 28 (paper) or March 31 (electronic).
5. Start nondiscrimination testing, Section 125 for cafeteria plans, and Section 105(h) if you’re self-funded, early enough in the plan year to actually correct a failing result before it becomes a compliance problem instead of after.

What We Found Checking Benefits Platforms for 2027 Readiness

We checked how five HR platforms commonly used for benefits administration, Rippling, Gusto, Paycor, ADP Workforce Now, and Employee Navigator, handle the annual limit refresh going into open enrollment. All five update HSA contribution limits automatically once the IRS confirms them, and none can display a number the IRS hasn’t published yet, which is exactly why this year’s FSA and 401(k) fields are the ones worth checking manually rather than trusting the platform default. The gap that actually causes problems isn’t the limit itself, it’s an employee re-electing the same dollar FSA amount as last year without realizing the cap moved, which under-elects relative to what they could actually set aside. If your platform doubles as your core HRIS, see HRIS vs. HCM vs. HRMS for how benefits administration typically fits inside that broader system, and whether your current platform actually owns this workflow end-to-end or just the data storage piece of it.

Who Actually Has to Do This

Every employer offering group health coverage runs some version of open enrollment, but the compliance stakes differ sharply depending on size and funding structure.

• Applicable Large Employers (50+ full-time equivalent employees): carry direct ACA employer mandate exposure, meaning the $3,780 and $5,670 penalty figures above are real numbers you could owe, and you’re responsible for 2027 Form 1095-C reporting.
• Employers under 50 FTEs: aren’t subject to the ACA employer mandate penalties, but still have ERISA notice and COBRA obligations for any group health plan offered, and Section 125 nondiscrimination testing applies regardless of headcount if you’re running a cafeteria plan.
• Self-funded plans: carry an extra layer, Section 105(h) nondiscrimination testing, on top of everything above.
• Fully insured plans: skip 105(h) testing but still need every required notice and an accurate SBC for each plan option offered.

Frequently Asked Questions

1. When is open enrollment for 2026?

If you mean the employer open enrollment happening right now, most companies run their window sometime between October and December 2026, setting up benefits for the 2027 plan year starting January 1. If you’re looking for the ACA Health Insurance Marketplace’s individual open enrollment for 2026 coverage, that window ran from November 2025 through mid-January 2026 and has already closed; it’s a separate process from employer group enrollment.

2. What is the ACA affordability percentage for 2027?

The 2027 ACA affordability percentage is 10.22%, up from 9.96% in 2026, and the first time this figure has exceeded 10%. It caps how much a full-time employee’s required contribution for the lowest-cost self-only coverage can be, expressed as a share of household income or one of the IRS-approved safe harbors, before an Applicable Large Employer risks a §4980H(b) penalty.

3. Is the 2027 FSA contribution limit official yet?

Not as of this writing. The projected 2027 health FSA limit is $3,500, up from $3,400 in 2026, but the IRS typically doesn’t confirm the actual figure until a revenue procedure released in October or November. Reconfirm the number before finalizing any enrollment materials or payroll configuration that depends on it.

4. What happens if an employer misses required open enrollment notice deadlines?

Missing notices like the SBC, Medicare Part D creditable coverage notice, or CHIP notice can expose an employer to ERISA-based penalties assessed per notice and, in some cases, per day of delay, separate from any ACA reporting penalties tied to late or incorrect Form 1095-C filings. The exact exposure depends on which notice was missed and whether the DOL or IRS treats the failure as willful.

5. What’s the difference between open enrollment and a special enrollment period?

Open enrollment is a fixed annual window every eligible employee can use to elect or change benefits, regardless of any life event. A special enrollment period is triggered by a specific qualifying life event, marriage, birth, loss of other coverage, and typically gives an employee 30 to 60 days from that event to make a change outside the normal window.

6. Do small employers have to run open enrollment?

Yes. Any employer offering a group health plan runs some form of open enrollment for its employees, regardless of headcount. What changes with size is compliance exposure: only Applicable Large Employers (generally 50 or more full-time equivalent employees) face ACA employer mandate penalties, while nondiscrimination testing requirements for cafeteria plans apply regardless of company size.