Maximum Taxable Earnings (Social Security)
The Social Security maximum taxable earnings limit is the annual wage ceiling above which earnings are not subject to the Social Security payroll tax (OASDI) and are not credited toward a worker's benefit calculation, set at $168,600 for 2024 and adjusted annually with national wage growth.
The maximum taxable earnings limit, also called the contribution and benefit base, serves a dual purpose in the Social Security system. First, it defines the cap on Social Security payroll tax liability for workers and their employers. Second, it defines the ceiling on creditable earnings for benefit calculation purposes. Wages above this threshold generate no additional Social Security tax obligation and contribute nothing additional to the worker's AIME or eventual PIA.
The limit is updated annually by the SSA using the national average wage index. In years where wages grow across the economy, the maximum taxable earnings limit rises correspondingly, maintaining the program's financing in relation to wage trends. The 2024 limit of $168,600 represents a substantial increase from the limit of $147,000 just two years earlier, reflecting the rapid wage growth of 2021-2022.
The combined Social Security payroll tax rate is 12.4%, split evenly between employee (6.2%) and employer (6.2%). Self-employed individuals pay the full 15.3% combined rate for FICA (including the 2.9% Medicare portion, which has no earnings ceiling). For a worker earning exactly at the maximum taxable earnings limit in 2024, the employee-side Social Security tax obligation is 6.2% of $168,600, or approximately $10,453 for the year.
There is an important asymmetry in how the maximum taxable earnings limit interacts with the PIA formula. Because the second bend point in the PIA formula is well below the maximum taxable earnings limit, earnings that push a worker's AIME above the second bend point yield only 15 cents of monthly PIA per dollar of additional AIME. High earners who consistently earn well above the maximum taxable earnings limit receive a low marginal Social Security return on the taxes paid at their income level.
The maximum taxable earnings limit is frequently discussed in the context of Social Security solvency proposals. One reform option that has been proposed repeatedly is either raising the limit, eliminating it entirely, or applying the tax to earnings above the limit without crediting those earnings toward benefits. Each approach would increase Social Security tax revenue but would have different distributional and incentive effects.
For workers tracking their Social Security benefit projections, understanding the maximum taxable earnings limit helps contextualize why their SSA Statement shows a benefit that appears modest relative to their high lifetime earnings.