Mid-Year Payroll Check: The Wage Base, the Extra Medicare Tax, and What to Verify

Payroll errors have a particular quality: they're small every pay period and large by December. A withholding rate that's slightly wrong in January produces a manageable correction in March and a genuine problem in January of the following year, when W-2s are due and corrections require amended forms.

We're at the midpoint of 2026. This is the natural time to verify a handful of numbers.

The Social Security wage base

For 2026, the Social Security taxable wage base is $184,500, up from $176,100 in 2025.

Social Security tax applies at 6.2% to wages up to that cap, withheld from the employee and matched by the employer. The maximum for each side is $11,439 per employee. Once an employee's wages with your company cross $184,500, Social Security withholding stops for the remainder of the year.

Two things to verify:

Your payroll tables were updated. If your system was still applying the 2025 cap of $176,100, you stopped withholding $8,400 too early for any employee who crossed it. That produces under-withholding, a W-2 correction, and an unhappy conversation.

Employees who will cross the cap are informed. An employee who hits $184,500 in October sees their take-home pay increase for the rest of the year. Employees frequently interpret this as a payroll error and ask about it. Getting ahead of the question is easier than explaining it after the fact.

Medicare has no cap, and there's a second tier

Medicare tax applies at 1.45% to all wages with no ceiling, matched by the employer.

On top of that, an Additional Medicare Tax of 0.9% applies to wages above $200,000 for a single filer and $250,000 for joint filers. Two features of this tax cause problems:

It is employee-only. The employer does not match the additional 0.9%.

The employer's withholding obligation is based on a flat $200,000 threshold per employee, regardless of the employee's actual filing status. You withhold once wages from your company exceed $200,000. If the employee's household situation means they owe more or less, that's reconciled on their personal return. Employers who try to account for an employee's marital status here create errors.

The wage base is per employer, not per person

An employee who worked for another company earlier in the year and earned $100,000 there starts fresh with you. You withhold Social Security tax on their wages from your company up to the full $184,500, even though the combined total exceeds the cap.

The employee recovers the excess as a credit on their personal return. Employers sometimes try to account for prior employment and stop withholding early. That's incorrect and it creates an under-withholding liability for the employer.

FUTA

The federal unemployment tax base remains $7,000 per employee at 6.0%, reduced to an effective 0.6% for employers who pay their state unemployment tax on time and operate in a state without a credit reduction. Credit reduction states change from year to year, so this is worth confirming rather than assuming.

While you're in there: three other things to check

Mileage reimbursement rates. The IRS changed the standard business mileage rate mid-year in 2026. Reimbursement programs still running on the January rate are under-reimbursing employees. This is worth a separate look.

Worker classification. Mid-year is a good time to review anyone treated as a contractor who functions like an employee. Classification errors compound and the exposure includes back payroll taxes, penalties, and interest.

Tip and overtime tracking. New W-2 reporting requirements for qualified tips and qualified overtime take effect for the 2026 tax year, with the forms due in January 2027. If your payroll system isn't already tracking these categories separately, the time to fix that is now, while there are still months of data to capture properly. Reconstructing a full year of qualified overtime in January is difficult and the penalties for incomplete W-2s are real.

Why mid-year rather than year-end

A withholding error caught in June affects six months of payroll and can often be corrected through adjusted withholding across the remaining pay periods. The same error caught in December affects twelve months, requires a lump-sum correction from the employee, and may need amended quarterly filings.

Payroll is one of the few areas where an hour of attention in June reliably saves several hours in January.

This article is general information, not tax advice for your specific situation. Payroll rules vary by state and change annually. Please talk with us before acting on anything here.