Social Security and Medicare on Your Pay Stub -- FICA

Two lines on your pay stub that never seem to change: Social Security and Medicare. Every paycheck, every period, they're there — 6.2% and 1.45% of your gross wages, taken out before you ever see the money. Understanding exactly how these work, why they're calculated the way they are, and what the limits mean for high earners makes you a more informed employee and helps you plan accurately.

What FICA Stands For

FICA stands for the Federal Insurance Contributions Act — the 1935 law that established the framework for Social Security, later expanded to include Medicare in 1965. FICA taxes fund two separate federal programs:

Old Age, Survivors, and Disability Insurance (OASDI): What most people call "Social Security." Funds retirement benefits, disability benefits, and survivors benefits for workers and their families.
Hospital Insurance (HI): What most people call "Medicare." Funds Medicare Part A, which covers hospital care for people 65 and older and certain disabled individuals.

On your pay stub, these appear as separate line items even though they're both FICA taxes. Common labels:

Social Security: "OASDI," "SS Tax," "Social Security," "Soc Sec"
Medicare: "Medicare," "Medicare Tax," "Med Tax," "HI" (Hospital Insurance)

Social Security: The Complete Picture

Employee Rate: 6.2%

You pay 6.2% of your gross wages to Social Security each pay period. This is the number you see on your stub.

Examples:

$1,000 weekly: $62.00 SS per period
$2,500 bi-weekly: $155.00 SS per period
$3,500 bi-weekly: $217.00 SS per period
$5,000 semi-monthly: $310.00 SS per period

Employer Rate: Also 6.2%

Your employer pays an additional 6.2% on your behalf — you don't see this on your stub because it comes from the employer, not from your paycheck. The combined rate is 12.4% of your wages going to Social Security. Your 6.2% + employer's 6.2% = 12.4% total contribution.

This employer match is why self-employed people face a higher effective rate: there is no separate employer to pay the second 6.2%, so self-employed workers owe both halves (see Self-Employed section below).

The 2024 Social Security Wage Base: $168,600

Social Security has a maximum taxable wage base. In 2024, that limit is $168,600. Once your cumulative earnings in a calendar year exceed $168,600, Social Security withholding stops completely for the rest of the year.

What this looks like on your stub: Around pay period 24 or 25 for a high earner, your Social Security line item drops to $0.00. It's not an error — it's the wage base limit cutting in.

For a $200,000/year earner paid bi-weekly (gross $7,692/period):

Periods 1–22: SS = $7,692 × 6.2% = $476.90/period
Period 22 YTD gross: $7,692 × 22 = $169,231 (just over the $168,600 limit)
SS stops during period 22 after the $168,600 threshold is crossed
Periods 23–26: SS = $0.00

When you hit the wage base mid-period (e.g., period 22), your employer withholds SS only on the portion up to $168,600. The exact stub will show a reduced SS amount in that transition period, then $0 thereafter.

The wage base adjusts annually for inflation. It was $160,200 in 2023, $168,600 in 2024. Historical context: in 1990 it was $51,300; in 2000 it was $76,200. The trend is a consistent increase of roughly 5% per year.

What Your YTD Social Security Column Shows

The YTD column for Social Security on your stub tracks your cumulative Social Security contributions from January 1. This matters for:

Tracking the wage base: When YTD gross approaches $168,600, you can anticipate when SS withholding will stop
Multiple job holders: If you work two W-2 jobs simultaneously, each employer withholds SS independently. If your combined earnings exceed $168,600, you'll have over-withheld SS. The IRS will refund the excess when you file your tax return (claimed on Form 1040 as "excess Social Security tax withheld")
W-2 verification: Box 4 (Social Security tax withheld) on your W-2 should match your December YTD SS total on your final stub. If it doesn't, that's a payroll error to correct with your employer

Medicare: The Complete Picture

Employee Rate: 1.45%

Medicare is simpler than Social Security: 1.45% of all wages with no wage base cap. Medicare continues on every dollar you earn, regardless of total annual compensation.

Examples:

$3,500 bi-weekly: $3,500 × 1.45% = $50.75/period
$10,000 bi-weekly: $10,000 × 1.45% = $145.00/period
$50,000 bi-weekly (executive): $50,000 × 1.45% = $725.00/period

Employer Rate: Also 1.45%

Same as Social Security: your employer pays an additional 1.45% on your behalf. Combined rate: 2.9%.

Additional Medicare Tax: 0.9% for High Earners

The Affordable Care Act (2013) introduced an additional 0.9% Medicare surtax on high earners, with no corresponding employer match:

Single filers: 0.9% on wages over $200,000
Married filing jointly: 0.9% on wages over $250,000
Married filing separately: 0.9% on wages over $125,000

When your wages exceed the threshold, your employer withholds the additional 0.9% only if you have a single employer and your wages from that employer exceed the threshold. If you have two W-2 jobs and neither employer sees wages over $200,000 from you alone, neither withholds the Additional Medicare Tax — but you'll still owe it if your combined wages cross the threshold. Reconcile at tax time on Form 8959.

What it looks like on your stub: Your Medicare line item might read $50.75 for most of the year. Once you cross $200,000 in wages from that employer, it jumps to $50.75 + additional 0.9% on each dollar above $200,000. Some payroll systems break this into a separate "Additional Medicare Tax" line; others fold it into the Medicare line.

Why Social Security and Medicare Show Up Separately

From a tax administration standpoint, they're separate programs with separate rates, separate wage bases (or lack thereof for Medicare), and separate trust funds. Combining them on a pay stub would obscure whether each program's rate is being applied correctly.

For W-2 purposes, they appear in separate boxes:

Box 4: Social Security tax withheld
Box 6: Medicare tax withheld

Box 3 (Social Security wages) and Box 5 (Medicare wages) may differ from Box 1 (federal taxable wages) because pre-tax deductions affect them differently. A 401(k) contribution reduces Box 1 (federal wages) but does NOT reduce Box 3 or 5 (FICA wages). Health insurance premiums reduce all three boxes (FICA-exempt under Section 125 plans).

Self-Employed FICA: The 15.3% Reality

If you're self-employed — sole proprietor, freelancer, gig worker — you owe both the employee AND employer portions of FICA, because you are both:

Social Security: 6.2% (employee) + 6.2% (employer) = 12.4%
Medicare: 1.45% + 1.45% = 2.9%
Total: 15.3%

The self-employment tax calculation uses 92.35% of net earnings (the percentage reflects the deductible employer share):

Net SE income: $60,000
SE tax base: $60,000 × 92.35% = $55,410
SE tax: $55,410 × 15.3% = $8,478

The "deduction" for the employer equivalent (50% of SE tax = $4,239) can be deducted on your 1040, reducing your adjusted gross income. But you still owe the full 15.3% on your SE tax base.

This is why there's a real economic difference between W-2 income and 1099 income at the same gross number. A W-2 employee earning $60,000 pays $3,720 in Social Security employee tax and the employer pays another $3,720 — but the employee only sees $3,720 as a deduction. A 1099 contractor earning $60,000 pays $8,478 in SE tax — effectively double the visible FICA hit.

Social Security Wage Base and the Argument Over It

The Social Security wage base ($168,600 in 2024) is a point of ongoing policy debate. Critics argue that the cap means high earners pay a lower effective FICA rate than lower-paid workers. A worker earning $50,000 pays 6.2% on 100% of their wages. A worker earning $300,000 pays 6.2% on only $168,600 of their wages — an effective SS rate of 3.5% on their total wages.

Medicare has no wage base, so the same comparison doesn't apply — a $300,000 earner pays 1.45% Medicare on all $300,000.

Proposals to raise or eliminate the SS wage base come up in nearly every Social Security solvency discussion. Eliminating the cap entirely would significantly increase contributions from high earners; raising it would generate additional revenue while maintaining some ceiling. What the current law says and what future law might say are separate questions — but understanding the current cap mechanics helps you plan.

How FICA Connects to Your Benefits

The money withheld under FICA isn't going into a personal account with your name on it — Social Security and Medicare operate as pay-as-you-go programs where current workers fund current beneficiaries. However, your FICA contributions do affect your future benefits:

Social Security credits: You earn up to 4 credits per year based on your earnings. You need 40 credits (10 years of work) to qualify for retirement benefits. Your benefit amount is calculated based on your highest 35 years of earnings.
Medicare eligibility: 40 quarters (10 years) of Medicare contributions qualifies you for premium-free Medicare Part A at 65.

The more you earn (up to the SS wage base), the higher your eventual Social Security benefit. This is why high-income workers close to retirement who delay claiming Social Security receive substantially higher monthly benefits than lower-income workers or early claimers.

For the complete deductions picture — what reduces your FICA wages versus your federal income tax wages and why it matters — see our complete deductions guide. And for the broader pay stub context, including all the fields that show up around these FICA lines, the full pay stub explainer covers every field with worked calculations. If you are self-employed and calculating your own self-employment tax obligations, see the quarterly taxes for freelancers guide for the payment schedule and estimated tax calculation process.