Do I have to pay FICA taxes on my earnings if I also collect Social Security?
Yes. There is no exemption for paying the Federal Insurance Contribution Act (FICA) payroll taxes that fund the Social Security and Medicare systems. As long as you work in a job that is covered by Social Security, FICA taxes will be withheld from your paycheck.
“Here's what happens if you collect Social Security early while working
To answer the most basic question, you absolutely can work, part- or full-time, while receiving Social Security benefits. However, there are rules that limit how much of your benefit you're allowed to keep depending on your claiming age, full retirement age (i.e., the age you become eligible to receive 100% of your monthly benefit, as determined by your birth year), and your earned income.
For example, anyone receiving Social Security benefits who won't reach their full retirement age in 2021 (or any current year) is subject to what's known as the retirement earnings test. The retirement earnings test allows the Social Security Administration to withhold some or all of your benefits based on much you earn. In 2021, early filers are allowed to earn up to $18,960 ($1,580 a month) before withholding kicks in.
If you earn over $18,960 in wages or salary, $1 in benefits will be withheld for every $2 in earnings above this threshold. The retirement earnings test might thus prevent you from double-dipping on income sources or paying off debt. ”
