Definition
Social Security tax is the 6.2% payroll tax withheld from your wages up to the annual Social Security wage base. In 2026, that base is $176,100 — meaning you pay 6.2% on your first $176,100 of wages, and nothing above that. Your employer pays a matching 6.2%.
Once you've earned $176,100 in a year, Social Security withholding stops for the rest of that year. If you have multiple employers and each withholds independently, you may over-pay Social Security — any excess is credited back to you when you file your return.
Self-employed individuals pay both the employee and employer shares — a combined rate of 12.4% — as part of self-employment tax.
How this affects your W-4
Social Security withholding is not controlled by your W-4 — it's calculated automatically at 6.2% of each paycheck, stopping once you hit the annual wage base. You cannot reduce or increase it via the W-4.
If you're self-employed and adjusting withholding from a W-2 job to cover SE tax, remember that SE tax includes 12.4% for Social Security plus 2.9% for Medicare — use Step 4c to add extra withholding to cover this.
See how social security tax affects your withholding
Use the free W-4 calculator to calculate your exact withholding with your specific situation.
Open the W-4 Calculator →