What Does Perjury Mean? Elements, Defenses & Federal Penalties

Perjury means deliberately lying about something important while you are under oath or have signed a statement under penalty of perjury. It is a federal felony punishable by up to five years in prison and a fine of as much as $250,000, and every state treats it as a felony too. The crime exists because courts, grand juries, and government agencies cannot function if people under a legal duty to tell the truth feel free to lie.

The Elements That Make a Statement Perjury

Federal perjury law lives in two statutes. 18 U.S.C. § 1621 is the general perjury statute and covers anyone who takes an oath before a court, officer, or other authorized person and then states something they do not believe to be true.¹ 18 U.S.C. § 1623 targets false statements made specifically in court or before a grand jury.²

Under either statute, a prosecutor has to prove three things: you were under oath or made a declaration under penalty of perjury, you made a false statement about something material to the proceeding, and you did it willfully, meaning you did not believe the statement was true when you made it.¹

Under Oath or Under Penalty of Perjury

The oath requirement is what separates perjury from other kinds of lying. It covers formal oaths administered in court, but it also reaches written statements. Under 28 U.S.C. § 1746, a document signed under penalty of perjury carries the same weight as a sworn statement, even without a notary.³ That is why tax returns, bankruptcy petitions, and immigration applications can give rise to perjury charges even though no one ever raised their right hand.

A Material False Statement

Not every lie under oath counts. The false statement has to be material, meaning it has a natural tendency to influence, or is capable of influencing, the decision the tribunal needs to make.⁴ A false statement that could not realistically affect the outcome falls outside the scope of the crime.

The Supreme Court held in United States v. Gaudin, 515 U.S. 506 (1995), that materiality is for the jury to decide, not the judge.⁵ In grand jury settings the standard is broader: because grand juries have wide investigative power, a lie only needs to potentially interfere with their line of inquiry.⁴ At trial, a lie about something that seems collateral, like your background, can still be material if it affects how jurors weigh your other testimony.

Willfulness

Perjury is not a strict-liability offense. You have to know your statement is false at the moment you make it.¹ Someone who gives wrong information because of a bad memory, honest confusion, or the stress of testifying has not committed perjury. Prosecutors prove the mental state through circumstantial evidence: how specific the question was, whether the person had access to accurate information, and whether the false answer fit a broader pattern of deception.

Where Perjury Can Happen

Perjury reaches well past the witness stand. Any setting where you are under oath or sign under penalty of perjury qualifies.

Depositions. Sworn testimony during the discovery phase of a lawsuit carries the same weight as courtroom testimony.
Affidavits and declarations signed under 28 U.S.C. § 1746.³
Government filings such as tax returns, bankruptcy petitions, and immigration applications.
Grand jury testimony, which falls specifically under § 1623.²
Congressional testimony, where witnesses are typically sworn in.¹

The federal statute applies whether the false statement was made inside or outside the United States.¹

What Isn’t Perjury

Several categories of misleading testimony fall outside the crime, and the distinctions matter.

Literally True Statements

In Bronston v. United States, 409 U.S. 352 (1973), the Supreme Court held that a literally true statement cannot support a perjury conviction, even if the witness was being deliberately evasive and the answer was misleading by implication. The Court put the responsibility on the questioning lawyer to ask a better follow-up question rather than on the witness to volunteer clarification.⁶

Honest Mistakes

Because willfulness is an element, a witness who sincerely believes an incorrect answer at the time they give it has not committed perjury. The protection exists so honest witnesses are not prosecuted for faulty memory.

Fundamentally Ambiguous Questions

If a question is so unclear that people of average intelligence could not agree on what it was asking, it cannot support a perjury charge as a matter of law. A question that is only arguably ambiguous can still produce a conviction if the jury finds that, given the witness’s understanding of what was being asked, the answer was false.

Recantation Under § 1623

Section 1623 lets a witness avoid prosecution by correcting a false statement during the same continuous court or grand jury proceeding. Two conditions apply: the false statement must not have substantially affected the proceeding yet, and it must not already be clear that the lie has been or is about to be exposed.² The defense rewards genuine self-correction, not a scramble once discovery feels inevitable. It applies only to § 1623 charges, not to § 1621.

Federal Penalties

Perjury is a federal felony. A conviction under either § 1621 or § 1623 carries up to five years in prison.¹ The court can also impose a fine of up to $250,000 under the general federal sentencing provisions.⁷ Perjury committed before the Foreign Intelligence Surveillance Court carries a higher ceiling of ten years.²

Every state also criminalizes perjury as a felony, though maximum sentences vary; depending on the jurisdiction, a conviction can carry anywhere from roughly four to fifteen years. Some states impose harsher penalties for false testimony in serious criminal trials than in civil proceedings.

A perjury conviction also carries lasting collateral consequences. The federal government classifies perjury as an aggravated felony for immigration purposes, which permanently bars a noncitizen convicted on or after November 29, 1990, from establishing the good moral character needed for naturalization.⁸ A felony conviction can also cost you professional licenses and firearm rights, and because perjury is a crime of dishonesty, it tends to follow a person into any future legal proceeding where their credibility matters.

Related Offenses

Subornation of Perjury

You can be prosecuted for perjury without ever taking the stand. Under 18 U.S.C. § 1622, anyone who convinces or pressures another person to commit perjury is guilty of subornation of perjury and faces the same maximum penalties, up to five years in prison and a fine of up to $250,000.⁹ A lawyer who coaches a witness to lie or a party who pays for false testimony can be charged under this statute.

False Statements Under § 1001

Lying to a federal agency or official when you are not under oath is a different crime. Under 18 U.S.C. § 1001, any knowing and material falsehood to a federal official can be prosecuted, with the same five-year maximum and $250,000 fine.¹⁰ The classic example is lying to an FBI agent during a voluntary interview. If you were under oath, expect a perjury charge; if you were not, the false-statements statute is the usual vehicle.

1
Office of the Law Revision Counsel. 18 USC 1621 Perjury Generally
2
Office of the Law Revision Counsel. 18 USC 1623 False Declarations Before Grand Jury or Court
3
Office of the Law Revision Counsel. 28 USC 1746 Unsworn Declarations Under Penalty of Perjury
4
United States Department of Justice Archives. 1748 Elements of Perjury Materiality
5
Justia Supreme Court. United States v Gaudin 515 US 506 (1995)
6
Legal Information Institute. Bronston v United States
7
Office of the Law Revision Counsel. 18 USC 3571 Sentence of Fine
8
USCIS. Chapter 4 Permanent Bars to Good Moral Character
9
Office of the Law Revision Counsel. 18 USC 1622 Subornation of Perjury
10
Office of the Law Revision Counsel. 18 USC 1001 Statements or Entries Generally