The 16th Amendment’s simple definition is this: it gives Congress the power to tax income directly, from any source, without having to divide the tax among the states based on population. Ratified on February 3, 1913, the amendment is a single sentence of 30 words, and it is the constitutional foundation for the federal income tax that Americans pay today.1National Archives. 16th Amendment to the U.S. Constitution: Federal Income Tax (1913)
The Exact Words
The full text reads: “The Congress shall have power to lay and collect taxes on incomes, from whatever source derived, without apportionment among the several States, and without regard to any census or enumeration.”2Constitution Annotated. U.S. Constitution – Sixteenth Amendment That is the entire amendment. No subsections, no exceptions written into the text itself.
What Each Part Means
Three ideas do all the work in that sentence.
Taxes on incomes. Congress can tax what people and businesses earn. Before the amendment, the federal government leaned on tariffs on imported goods and excise taxes on things like alcohol and tobacco. Those taxes hit consumers at the register regardless of how much they made. Taxing income is a different tool, aimed at earnings rather than purchases.
From whatever source derived. The tax reach is not limited to wages. It covers business profits, interest, dividends, rent, capital gains on the sale of property, royalties, and virtually any other financial gain. Congress carried that phrase directly into the tax code at 26 U.S.C. § 61, which defines gross income as “all income from whatever source derived” and then gives a list of examples that is explicitly non-exhaustive.3Office of the Law Revision Counsel. 26 USC 61 – Gross Income Defined If an activity produces economic gain, the default assumption is that it is taxable unless a statute says otherwise.
Without apportionment. This is the phrase that made the amendment necessary in the first place. It means the federal government can tax individuals directly on what they earn, rather than deciding on a total dollar amount and dividing that total among the states in proportion to population.
Why It Was Added
The original Constitution allowed Congress to impose “direct taxes,” but Article I, Section 9 required that any such tax be divided among the states in proportion to population.4Constitution Annotated. Article I Section 9 – Powers Denied Congress In practice, Congress would decide how much it wanted to raise and then bill each state its population share.5Constitution Annotated. ArtI.S9.C4.1 Overview of Direct Taxes A populous but poor state could owe the same total as a smaller, wealthier one. Taxing individuals on their actual earnings did not fit inside that framework.
Congress tried an income tax anyway in 1894. The Supreme Court struck it down in Pollock v. Farmers’ Loan & Trust Co. (1895), holding that a tax on income from real estate and municipal bonds was a direct tax that had to be apportioned by population, which the 1894 law did not do.6Justia. Pollock v. Farmers’ Loan and Trust Co. The ruling effectively blocked a federal income tax under the existing Constitution. The 16th Amendment, proposed by Congress in 1909 and ratified in 1913, was written specifically to undo that obstacle.1National Archives. 16th Amendment to the U.S. Constitution: Federal Income Tax (1913)
What Counts as Taxable Income Today
The plain reach of “from whatever source derived” covers most of the money a person is likely to receive in a year. Common categories include:
- Wages, salaries, commissions, tips, and most fringe benefits from a job.
- Profits from running a business, whether as a sole proprietor, partner, or corporation.
- Interest, dividends, royalties, and annuity payments.
- Gains from selling stocks, real estate, or other property.
- Rent collected from tenants.
- Gambling winnings, prizes, forgiven debt, pension distributions, and income from trusts and estates.
The list in § 61 is deliberately open-ended. Something new, like a form of digital earnings that did not exist when the code was written, still falls inside “whatever source derived” if it produces economic gain.
What the Amendment Doesn’t Reach
Even with that broad reach, some money you receive is not treated as income. These exclusions are written into the tax code by Congress, not carved out by the amendment itself.
Gifts and inheritances are not counted as income to the person receiving them. A separate gift tax may apply to the giver, and an estate may owe tax on its own, but the recipient does not report the gift or inheritance as earnings.7Office of the Law Revision Counsel. 26 USC 102 – Gifts and Inheritances Life insurance proceeds paid because the insured person died are generally not taxable to the beneficiary.8Internal Revenue Service. Life Insurance and Disability Insurance Proceeds Employer-paid health insurance premiums and contributions to qualified retirement plans are excluded from taxable income in the year they are made.
There is a pattern worth noticing. The original transfer is often tax-free, but anything that transfer later produces is taxable. Inherit a rental property and the inheritance itself is not income, but every rent check that property generates afterward is. Interest earned on a life insurance payout after it lands in your account is taxable, even though the payout itself was not.
Progressive Rates and Direct Taxation
Because the amendment removed the apportionment requirement, Congress could design an income tax that varies by how much a person earns. That is what a progressive tax system means: higher earners pay a higher percentage on the top portion of their income. Only the dollars that fall inside a given bracket are taxed at that bracket’s rate, so moving into a higher bracket does not push all of a person’s earlier income up to the higher rate.
The rules that set brackets, deductions, credits, and filing requirements are written by Congress and collected in the Internal Revenue Code, which occupies Title 26 of the United States Code.9Internal Revenue Service. Tax Code, Regulations and Official Guidance The IRS administers those rules but does not write them. The 16th Amendment supplies the authority; the code supplies the details.
Attempts to Argue It Away
The amendment was challenged almost immediately. In Brushaber v. Union Pacific Railroad Co. (1916), the Supreme Court upheld the federal income tax passed under it. The Court said the amendment’s “whole purpose” was to free income taxes from the apportionment requirement, not to create a narrow or limited taxing power, and it rejected due process and uniformity challenges.10Legal Information Institute. Brushaber v. Union Pacific Railroad Co.
More than a century later, arguments still circulate online that the amendment was never properly ratified, that income taxes are voluntary, or that wages are not income. Federal courts have rejected these theories consistently, and the IRS treats returns based on them as frivolous. Filing on that basis can add a $5,000 frivolous return penalty on top of any tax owed. The settled reading of the amendment is the one the Supreme Court gave it in 1916 and has never walked back.
Why It Still Matters
Before 1913, the federal government relied mainly on tariffs and excise taxes, which fell on consumers regardless of income. The 16th Amendment made it constitutionally possible to fund the federal government from earnings instead of purchases, and to vary the burden by how much a taxpayer makes. Individual income taxes now account for roughly half of federal revenue in a typical year. Every part of that structure, from the withholding on a paycheck to the April filing deadline, rests on the one sentence ratified in 1913.