2018 Social Security Tax Calculation Change in 2018

Multiple Calculator release 2.0.7. Category: Finance. Check the displayed formula, units, assumptions, and limitations before use. Methodology · Report an error · Disclaimer

Reviewed by Calculator Editorial Team

In 2018, the Social Security tax calculation underwent significant changes that affected how much was deducted from your paycheck. These changes were part of broader adjustments to the tax system to ensure long-term sustainability. This guide explains the key changes, how they impacted your paycheck, and provides a calculator to determine your exact deductions.

What Changed in 2018?

The primary change in 2018 was the adjustment to the Social Security wage base. The wage base is the maximum amount of earnings subject to Social Security tax. In 2018, the wage base was increased from $118,500 to $137,700. This means that in 2018, the first $137,700 of your earnings were subject to Social Security tax, up from $118,500 in previous years.

Social Security Tax Rate: 6.2% for both the employee and employer (total 12.4%)

Medicare Tax Rate: 1.45% for both the employee and employer (total 2.9%)

Additionally, the taxable earnings threshold for Social Security benefits was adjusted. The annual earnings test threshold was increased from $16,920 to $18,240. This means that if your earnings exceed $18,240 in a year, you may be subject to a reduction in your Social Security benefits.

How It Affected Your Paycheck

The increase in the wage base meant that more of your earnings were subject to Social Security tax. If you earned more than $137,700 in 2018, the additional earnings above this threshold were not subject to Social Security tax. However, if you earned less than $137,700, the tax rate remained the same as in previous years.

The adjustment to the taxable earnings threshold for Social Security benefits meant that more people may have been subject to a reduction in their benefits. If your earnings exceeded $18,240 in a year, you may have received a lower monthly benefit.

Note: The changes in 2018 were part of a broader effort to ensure the long-term sustainability of the Social Security system. The adjustments were made to prevent the system from becoming unsustainable due to the aging population and increasing life expectancy.

Calculation Method

The Social Security tax is calculated based on your earnings. The taxable earnings are the first $137,700 of your earnings in 2018. The Social Security tax rate is 6.2% for both the employee and employer, resulting in a total tax rate of 12.4%.

Social Security Tax Calculation:

Taxable Earnings = Min(Annual Earnings, $137,700)

Social Security Tax = Taxable Earnings × 6.2%

The Medicare tax is calculated on all earnings, with a rate of 1.45% for both the employee and employer, resulting in a total tax rate of 2.9%.

Medicare Tax Calculation:

Medicare Tax = Annual Earnings × 1.45%

To determine your total Social Security and Medicare tax, you can use the calculator on the right. Simply enter your annual earnings, and the calculator will compute the tax amounts for you.

Worked Example

Let's consider an example to illustrate how the changes in 2018 affected your paycheck. Suppose you earned $150,000 in 2018.

Calculation	Amount
Annual Earnings	$150,000
Taxable Earnings (Min of Earnings and $137,700)	$137,700
Social Security Tax (6.2%)	$8,500.40
Medicare Tax (1.45%)	$2,175.00
Total Tax	$10,675.40

In this example, the Social Security tax was calculated on the first $137,700 of your earnings, and the Medicare tax was calculated on all $150,000 of your earnings. The total tax amount was $10,675.40.

Frequently Asked Questions

What was the main change to Social Security tax in 2018?: The main change was the increase in the wage base from $118,500 to $137,700. This meant that more of your earnings were subject to Social Security tax.
How did the change in the wage base affect my paycheck?: If you earned more than $137,700, the additional earnings above this threshold were not subject to Social Security tax. If you earned less than $137,700, the tax rate remained the same as in previous years.
What was the taxable earnings threshold for Social Security benefits in 2018?: The taxable earnings threshold for Social Security benefits was increased from $16,920 to $18,240. If your earnings exceeded this threshold in a year, you may have been subject to a reduction in your benefits.
How is the Social Security tax calculated?: The Social Security tax is calculated on the first $137,700 of your earnings, with a rate of 6.2% for both the employee and employer, resulting in a total tax rate of 12.4%.
How is the Medicare tax calculated?: The Medicare tax is calculated on all earnings, with a rate of 1.45% for both the employee and employer, resulting in a total tax rate of 2.9%.