How Social Security Gets Its Money

Social Security is funded by payroll taxes — money taken from your paycheque and matched by your employer. The tax rate is 12.4 percent of your wages (you pay half, your employer pays half), up to a yearly earnings cap that changes each year. Self-employed people pay the full 12.4 percent themselves. These taxes go into two separate trust funds: one for retirement and survivor benefits, and one for disability benefits.

When you work, your employer sends your Social Security taxes to the U.S. Treasury. The money does not sit in an account with your name on it. Instead, it goes into a shared pool that pays current beneficiaries — people already retired, disabled, or receiving survivor benefits. This is called a pay-as-you-go system. The taxes you pay today fund the people receiving benefits today, and when you retire, taxes paid by people still working will fund your benefits.

The earnings cap means high earners pay Social Security tax only on income up to a certain threshold. In 2024, that cap was $168,600 — so someone earning $200,000 pays tax only on the first $168,600. The cap rises each year based on wage growth. This is why Social Security replaces a larger percentage of income for lower earners than for higher earners.

Key Takeaways

  • Social Security is funded by a 12.4 percent payroll tax split between you and your employer, collected on wages up to an annual cap that changes yearly.
  • Your taxes do not go into a personal account — they fund benefits for current retirees, disabled workers, and survivors right now.
  • The trust funds that hold this money are separate for retirement benefits and disability benefits, and each one's balance is tracked independently.
  • When the trust funds run low, incoming taxes cover only a portion of scheduled benefits unless Congress changes the law.

What Happens to the Money You Pay In

Each month, the Social Security Administration pays out benefits to roughly 67 million people. These payments come from the payroll taxes collected that month, plus interest earned on the trust fund reserves. In years when tax income exceeds benefit payments, the surplus goes into the trust fund as a cushion. In years when benefit payments exceed tax income, the trust fund balance shrinks as it covers the shortfall.

The trust fund balance matters because it determines how long the system can pay full benefits if tax income drops or if more people retire than expected. The trustees who oversee Social Security publish an annual report showing whether each trust fund is growing or shrinking and when reserves might run out if current law does not change.

The Trust Funds and Their Separate Balances

Social Security maintains two trust funds: the Old-Age and Survivors Insurance (OASI) Trust Fund and the Disability Insurance (DI) Trust Fund. They are funded by the same payroll tax but keep separate reserves and pay different types of benefits. The OASI fund pays retirement benefits and survivor benefits to families of deceased workers. The DI fund pays benefits to workers under full retirement age who cannot work due to disability, plus their family members.

The two funds can have very different financial pictures. The DI fund, which covers a smaller population, has historically had different reserve levels than the OASI fund. Congress can shift tax revenue between them if one fund is depleting faster than the other, which it has done in the past. However, the total payroll tax rate of 12.4 percent cannot be changed without new legislation.

When Tax Income Falls Short of Benefit Payments

In recent years, Social Security has paid out more in benefits each month than it collects in payroll taxes. This is not a sudden crisis — it was projected decades ago and reflects the retirement of the Baby Boom generation. When outflows exceed inflows, the trust fund reserves cover the difference. The reserves are invested in U.S. Treasury bonds, which earn interest and help sustain the fund.

The trustees estimate when each trust fund's reserves will be depleted if current law stays unchanged. When reserves run out, incoming payroll taxes can still cover a portion of scheduled benefits — roughly 77 to 80 percent, depending on the fund and the year. Congress would need to act before that point by raising the payroll tax, raising the earnings cap, reducing benefits, raising the full retirement age, or some combination of these changes.

How the Earnings Cap Affects Funding

The payroll tax cap means that high earners contribute a smaller percentage of their total income to Social Security than lower earners do. A person earning $50,000 pays tax on all of it. A person earning $500,000 pays tax only on the first $168,600 (in 2024), so their effective tax rate is much lower. Raising or eliminating the cap would increase revenue to the trust funds, which is why it appears in many proposals to strengthen Social Security's finances.

The cap is adjusted each January based on the previous year's average wage growth. This means the threshold rises most years, but the percentage of total wages subject to the tax can still decline if high earners' wages grow faster than average wages. Some policy proposals would explore the tax to all wages above the current cap, which would significantly increase revenue without raising the tax rate.

Interest and Investment Income

The trust fund reserves are not held in cash. They are invested in U.S. Treasury bonds, which pay interest. This interest income is part of what sustains the funds when benefit payments exceed tax revenue. The interest rate depends on the bond yields at the time the bonds are purchased, so it fluctuates with broader interest rates in the economy.

The interest earned on the trust fund reserves is substantial — in some years it represents 10 to 15 percent of total trust fund income. As the reserves shrink, the interest income shrinks with them, which is another reason why the timing of when reserves might be depleted matters. A smaller reserve balance generates less interest, making the shortfall between taxes and benefits harder to cover.

What Happens If Congress Does Not Act

If the trust fund reserves are depleted and Congress has not changed the law, Social Security will not stop paying benefits. Instead, the program will pay benefits from incoming payroll taxes only. The trustees estimate this would allow the program to pay roughly 77 to 80 percent of scheduled benefits, depending on the fund and the year. The exact percentage depends on how many workers are paying in relative to how many people are receiving benefits.

This would mean automatic benefit cuts across the board unless Congress acts. Congress could prevent this by raising taxes, raising the cap, reducing benefits for higher earners, raising the full retirement age, or using general revenue from the Treasury. The longer Congress waits to act, the larger the adjustment would need to be to restore full solvency.

Frequently Asked Questions

Does my Social Security tax go into an account with my name on it?

No. Your payroll taxes go into a shared trust fund that pays current beneficiaries. The system is designed so that taxes from current workers fund benefits for current retirees. Your work record is tracked to calculate your benefit amount when you retire, but the money you pay in does not sit in a personal account waiting for you.

Why do self-employed people pay more in Social Security tax?

Self-employed people pay both the employee and employer portions of the payroll tax — 12.4 percent total instead of 6.2 percent. This is because there is no employer to split the cost. However, self-employed people can deduct half of their Social Security tax as a business expense, which reduces their taxable income.

What happens to Social Security taxes if I earn more than the cap?

You stop paying Social Security tax once your earnings reach the yearly cap. In 2024, the cap was $168,600, so earnings above that amount are not subject to the 12.4 percent payroll tax. However, those earnings are still subject to Medicare tax (1.45 percent), which has no cap. The Social Security cap rises each year based on wage growth.

Can Congress use general tax revenue to fund Social Security?

Congress could change the law to allow general Treasury revenue to fund Social Security, but it has not done so. Social Security is currently funded only by payroll taxes and the interest earned on trust fund reserves. Any change to this funding structure would require new legislation.

How often does the trust fund balance change?

The trust fund balance changes monthly as taxes come in and benefits go out. The trustees publish detailed annual reports showing the fund's status and projections for when reserves might be depleted. These reports are updated each year as new data on wages, life expectancy, and benefit claims becomes available.