The age of consent is the minimum age at which a person can legally agree to sexual activity, and it works less like a single rule than a stack of them. A baseline number sets the floor, but age gaps between partners, positions of authority, strict-liability rules, and even where the conduct happens can all change whether a relationship is legal or a felony. Understanding how age of consent works means understanding all of those layers, because the baseline number alone rarely tells you the answer.
The Baseline Age Depends on Where You Are
In the United States, every state sets its own age of consent. In 34 states the age is 16. Six states set it at 17, and the remaining 11 set it at 18.1Office of the Assistant Secretary for Planning and Evaluation (ASPE). Statutory Rape: A Guide to State Laws and Reporting Requirements Crossing a state line can change whether a particular relationship is legal, and ignorance of the local rule is not a defense.
On federal property, military bases, tribal lands, and in federal prisons, state law does not apply. Federal statute makes it a crime to engage in sexual activity with someone who is at least 12 but under 16 if the older person is at least four years older, punishable by up to 15 years in prison.2Office of the Law Revision Counsel. 18 USC 2243 – Sexual Abuse of a Minor or Ward For victims under 12, the penalties jump to a mandatory minimum of 30 years and a maximum of life.3Office of the Law Revision Counsel. 18 U.S. Code 2241 – Aggravated Sexual Abuse
Globally, most countries set the age between 14 and 18, with 16 the single most common threshold. Germany and Italy set the baseline at 14, though Italy raises it to 16 when the older person holds a position of trust and permits relationships between minors from age 13 as long as the age gap is no more than four years. South Korea enforces 16 strictly, and parental consent cannot lower it.
Close-in-Age Exemptions Change the Math
Many jurisdictions recognize that a 17-year-old with a 15-year-old partner is a different situation than an adult targeting a child. Close-in-age exemptions, sometimes called Romeo and Juliet provisions, create a legal safe harbor when both people fall within a defined age range. They do not lower the age of consent itself.
The details vary. Some states allow a two-year gap, others three or four. Some require the younger person to be at least 14 or 15; others set no floor. A relationship legal in one state can be a felony in the next. These exemptions also affect whether a conviction triggers sex offender registration, which is often the most serious consequence for young defendants.
Not every jurisdiction has these provisions. Where they do not exist, prosecutors technically have the power to charge two teenagers in a consensual relationship, and whether they actually do depends on local discretion.
Authority Figures Raise the Age
Being above the general age of consent does not always make a relationship legal. Most legal systems impose a higher threshold when the older person holds power over the younger one. Teachers, coaches, employers, religious leaders, and foster parents are common examples. The reasoning is that the power imbalance makes freely given consent difficult or impossible.
In the United States, most states criminalize sexual relationships between authority figures and minors even when the minor is above the state’s general age of consent. A 17-year-old who can legally consent to a same-age partner may not be able to consent to a relationship with a teacher, regardless of what both parties say.
The United Kingdom takes a similar approach. Under the Sexual Offences Act 2003, any sexual activity between someone in a position of trust and a person under 18 is a criminal offense, even though the general age of consent is 16, and conviction carries up to five years in prison.4Legislation.gov.uk. Sexual Offences Act 2003 – Abuse of Position of Trust
Why “I Didn’t Know Their Age” Almost Never Works
In most U.S. states, statutory rape is a strict liability crime. The prosecution does not need to prove the defendant knew the other person was underage. It does not matter if the minor lied about their age, showed a fake ID, or looked older. If the person was below the age of consent, the crime is complete.
The reasoning is that the state’s interest in protecting children outweighs the unfairness to a defendant who was deceived. Courts have held that the defendant intended to engage in the sexual act voluntarily, and that is enough intent to support a conviction.
A small number of jurisdictions have moved away from strict liability. California’s courts have recognized a defense of reasonable and good-faith belief that the partner was of legal age. Federal law allows a narrow reasonable-belief defense for offenses involving minors between 12 and 16.2Office of the Law Revision Counsel. 18 USC 2243 – Sexual Abuse of a Minor or Ward These are exceptions. The default rule is that the defendant bears the risk of being wrong.
Sexting Can Carry Harsher Penalties Than Sex
One of the stranger consequences of how these laws interact involves sexting. In many states, two 16-year-olds can legally have sex but commit a felony if they exchange explicit photos of each other. The photos are classified as child pornography under statutes written before smartphones existed, and those laws typically carry far harsher penalties than the underlying sexual conduct.
A growing number of states have enacted teen sexting laws that reduce the charge to a misdemeanor or divert the case out of the criminal system. Coverage is uneven. In states without these targeted laws, a teenager who sends a consensual photo to a same-age partner can face felony child pornography charges and sex offender registration.
Traveling Abroad Does Not Erase U.S. Law
U.S. citizens and legal permanent residents cannot escape American law by traveling to a country with a lower age of consent. Federal law makes it a crime to travel from the United States to a foreign country and engage in sexual conduct with anyone under 18, even if the conduct is legal where it occurs.5U.S. Department of Justice. Citizens Guide to U.S. Federal Law on the Extraterritorial Sexual Exploitation of Children Traveling with the intent to engage in that conduct is also a crime, even if the person never follows through.6Office of the Law Revision Counsel. 18 U.S. Code 2423 – Transportation of Minors
Both offenses carry up to 30 years in federal prison.5U.S. Department of Justice. Citizens Guide to U.S. Federal Law on the Extraterritorial Sexual Exploitation of Children For all of the federal travel provisions, anyone under 18 is considered a child regardless of the foreign country’s age of consent. The Department of Justice maintains a dedicated unit that prosecutes these cases.
Criminal Penalties and Sex Offender Registration
Penalties for violating age-of-consent laws vary based on the ages involved, the age gap, and aggravating factors like force or a position of authority. At the federal level, sexual abuse of a minor between 12 and 16 carries up to 15 years.2Office of the Law Revision Counsel. 18 USC 2243 – Sexual Abuse of a Minor or Ward When the victim is under 12, or when force or threats are involved with a victim under 16, the mandatory minimum jumps to 30 years, with a maximum of life.3Office of the Law Revision Counsel. 18 U.S. Code 2241 – Aggravated Sexual Abuse A second federal conviction for aggravated sexual abuse of a child triggers a mandatory life sentence.
Beyond prison, conviction typically requires registration as a sex offender under the federal Sex Offender Registration and Notification Act (SORNA). The registration system uses three tiers based on the severity of the offense.7Office of the Law Revision Counsel. 34 U.S. Code 20911 – Relevant Definitions, Including Amie Zyla Expansion of Sex Offender Definition and Two-Strike Rule Tier I carries a 15-year registration period, reducible to 10 years with a clean record. Tier II carries a 25-year period and covers offenses like sex trafficking of minors and abusive sexual contact with a child. Tier III is lifetime registration, reserved for the most serious offenses including aggravated sexual abuse.
Registration carries consequences that outlast the prison sentence by decades. Registered offenders face restrictions on where they can live, where they can work, and in some cases where they can be present. Failing to register or update a registration is itself a federal crime carrying up to 10 years in prison.8U.S. Sentencing Commission. Primer on Sex Offenses: Sexual Abuse and Failure to Register Offenses
How Long Prosecutors Have to Bring Charges
Time limits vary by jurisdiction and severity. At the federal level, there is effectively no deadline for sexual offenses against children: prosecution is permitted during the entire life of the victim, or for 10 years after the offense, whichever is longer.9Office of the Law Revision Counsel. 18 U.S. Code 3283 – Offenses Against Children
State law varies widely. Some states have eliminated the statute of limitations for rape and sexual offenses against minors entirely. Others impose deadlines that range from a few years to several decades. Many extend or restart the clock when DNA evidence becomes available, or toll the limitation period while the victim is still a minor. Assuming that time has closed the door is a bad bet in a growing number of jurisdictions.