Fact check: What percentage of Social Security/Medicare payroll tax revenue came from undocumented workers in 2019–2024?

Executive summary — Short, clear accounting of the bottom line

Undocumented workers paid an estimated $25.6–$26 billion into Social Security and about $6.4 billion into Medicare in 2022, yielding roughly a little over 2 percent of combined Social Security and Medicare payroll‑tax receipts for that year when compared with ~ $1.6 trillion in total payroll tax collections — a figure that analysts have used to represent the 2019–2024 period in the absence of annually varying breakdowns ^[1]. Multiple independent research groups and government trustees’ summaries converge on the same order of magnitude for 2022 contributions, but the precise percentage for 2019–2024 depends on assumptions about year‑to‑year stability, the treatment of off‑the‑books earnings, and whether one counts only payroll taxes or broader fiscal contributions ^{[2] [3] [1]}.

1. What the competing claims actually state — straightforward extraction of the headline figures

Several recent reports converge on a consistent headline: undocumented workers paid roughly $96–97 billion in federal, state, and local taxes in 2022, with about $25.6–26 billion identified as Social Security (OASDI) payroll taxes and about $6.4 billion as Medicare payroll taxes, yielding a combined ~$32.0–32.1 billion in payroll contributions for that year ^{[2] [1] [4] [3]}. The Social Security trustees’ summaries and independent research groups repeat the same ballpark Social Security figure for 2022, and analysts who compare that total to aggregate payroll tax receipts — approximately $1.2 trillion for Social Security and $400 billion for Medicare in 2022 — calculate that undocumented workers supplied just over 2 percent of combined payroll‑tax revenue ^{[1] [5]}. These numbers are cited repeatedly across the supplied analyses.

2. How the percentage calculation is made — following the arithmetic and assumptions

The percentage emerges from dividing the ITEP/related estimates of undocumented workers’ payroll‑tax payments (about $32.1 billion) by the sum of federal payroll‑tax receipts for the programs they help fund (about $1.6 trillion total for Social Security and Medicare in 2022), which yields ≈2.0–2.1 percent ^[1]. That arithmetic assumes the 2022 snapshot is representative of the 2019–2024 interval and that collections are aptly summarized by the single‑year totals used. Key assumptions include year‑to‑year stability of undocumented employment, consistency in taxpayment methods (e.g., use of ITINs or false SSNs), and inclusion only of payroll taxes rather than net fiscal effects such as consumption taxes or benefits received ^{[4] [6]}.

3. Where analysts agree and where they diverge — reconciling different emphases

Analysts agree on the order of magnitude: undocumented workers are a nontrivial but not dominant source of payroll revenue, contributing tens of billions yearly and roughly 2 percent of combined payroll receipts when using 2022 figures as representative ^{[2] [3] [1]}. Differences arise in emphasis and scope: some studies present the figure to show a net fiscal contribution to trust funds, while others highlight that undocumented workers are barred from receiving benefits tied to those taxes — an argument used in different policy discussions ^{[2] [1] [5]}. Methodological variation, including whether to count state and local taxes or to extrapolate from sample surveys of undocumented populations, explains most of the divergence in totals and interpretation ^{[4] [6]}.

4. Alternative evidence and additional context analysts use — beyond the simple percent

Other research cited by analysts places undocumented contributions in a broader fiscal frame, estimating per‑capita net effects on Medicare or long‑term impacts on the Social Security trust fund, sometimes finding that immigrants overall (documented and undocumented) may subsidize program solvency in certain periods ^{[7] [5]}. The tax mechanics — flat payroll‑tax rates of 6.2 percent for Social Security and 1.45 percent for Medicare on employee wages — mean undocumented wages, when reported, are taxed at the same statutory rates, which supports the arithmetic used in these studies ^[6]. These contextual points matter for understanding how a payroll‑tax percentage translates into broader fiscal outcomes.

5. What this does and does not prove — caveats and policy‑relevant omissions

The 2 percent figure is a useful descriptor but not a definitive statement about net fiscal burden, benefit eligibility, or policy choices. It does not capture off‑the‑books work that escapes taxation, nor does it show whether undocumented workers’ payroll contributions are offset by use of public services at state and local levels. The studies rely on demographic and earnings estimates that can shift with migration flows, enforcement changes, or economic cycles; thus, extrapolating a single year’s estimate across 2019–2024 introduces uncertainty ^{[2] [1]}. Policymakers should treat the percentage as an evidence‑based estimate useful for budgeting conversations, not as a precise ledger entry.

6. Bottom line for readers and decisionmakers — measured, evidence‑based conclusion

Multiple independent analyses and trustee summaries converge on a 2022 payroll‑tax contribution from undocumented workers of about $32 billion, which equates to a bit over 2 percent of combined Social Security and Medicare payroll collections when using 2022 totals as representative of 2019–2024 ^{[1] [3]}. That conclusion is robust in magnitude but sensitive in detail to assumptions about underreporting, annual variation, and whether one assesses payroll taxes alone or broader fiscal impacts. Stakeholders should use this anchored estimate as a starting point while recognizing the methodological caveats documented above ^{[4] [5]}.