In this article
Colorado's age-gap rules use two different brackets: under fifteen, and fifteen or sixteen. For specified sexual penetration or intrusion under §18-3-402, the age-based provisions use a gap of at least four years in the first bracket and at least ten years in the second. Those numbers describe elements of particular offenses. They are not a general license for every kind of sexual conduct below the stated gap.
Ordinary dating is a separate question. Calling someone a boyfriend, girlfriend, or partner does not itself establish the sexual conduct these sections require. To understand a particular situation, start with the younger person's exact age, both birthdays, the conduct involved, and whether one person holds a position of trust.
The two brackets in the current Criminal Code
The 2026 Colorado Revised Statutes provide the starting point. Section 18-3-402(1)(d) addresses a person under fifteen and an actor at least four years older. Section 18-3-402(1)(e) addresses a person who has reached fifteen but has not reached seventeen and an actor at least ten years older. Both provisions include a nonspouse condition.
The practical distinction is easiest to see in a small table. This table concerns only these two age-based provisions of §18-3-402, not the entire criminal code.
| Younger person's age at the event | Age difference specified in the provision |
|---|---|
| Under fifteen | Actor at least four years older |
| Fifteen or sixteen | Actor at least ten years older |
| Seventeen or older | Outside these two younger-person brackets |
The final row does not mean all sexual activity involving a seventeen-year-old is lawful. Other parts of the same section address lack of consent, incapacity, physical helplessness, and certain abuses of authority. Other statutes address additional circumstances.
Why “within four years” can be misleading
People often describe Colorado as having a four-year exception. That shorthand leaves two questions unanswered: Which younger-person bracket applies, and does the boundary include exactly four years?
For the under-fifteen provision, the statutory threshold is at least four years. An exact four-year difference therefore satisfies that age-gap element. A difference of three years and eleven months does not. Calling both situations “within about four years” loses a distinction that the statute makes important.
Suppose one person was born on June 12, 2008, and the other on June 12, 2012. During the period when the younger person is fourteen, their gap is exactly four years. Moving the older person's birthday to July 12, 2008, produces a gap of three years and eleven months instead. These examples illustrate the arithmetic only; they do not resolve consent, authority, conduct, or other possible offenses.
Use complete dates of birth. Subtracting the ages people give at a party can be wrong by nearly a year because their birthdays may fall in different months.
The fifteenth birthday changes the relevant bracket
A couple's actual age difference stays constant, but the younger person's statutory category can change. That is why the event date belongs beside the birthdays in any careful analysis.
Imagine two people exactly five years apart. Before the younger person's fifteenth birthday, that gap meets the four-year element in subsection (1)(d). After that birthday, the younger person falls into the fifteen-or-sixteen bracket, whose age-gap element is ten years. The five-year difference does not meet that element.
That observation is limited to the age-based clauses. It does not erase an earlier event, establish that a later event was consensual, or decide whether a separate offense applies. A single relationship can involve events that require different legal analyses at different times.
The same caution applies at seventeen. Leaving the age bracket in subsection (1)(e) changes that particular inquiry. It does not cancel protections against nonconsensual conduct or against sexual contact by someone in a position of trust.
Sexual contact has its own provision
Section 18-3-402 concerns sexual intrusion or sexual penetration, as those terms are legally defined. Sexual contact is addressed separately, including in §18-3-405, titled sexual assault on a child.
Under §18-3-405(1), the age-based structure involves a person under fifteen and an actor at least four years older, along with knowingly subjecting the person to sexual contact and the statute's nonspouse condition. The resemblance to subsection (1)(d) does not make the two sections interchangeable. They describe different conduct and contain their own additional provisions.
A reader should therefore resist asking only, “What is Colorado's age gap?” A more useful question is, “Which statute governs the conduct being discussed, and what does that statute require?” The distinction also explains why a search result about intercourse may not answer a question about touching.
There is no need to publish intimate details online to make that distinction. A lawyer can identify the relevant legal category in a confidential consultation and explain which facts affect it.
A position of trust changes the analysis
Section 18-3-405.3 addresses sexual contact involving a child under eighteen when the actor occupies a position of trust with respect to that child. Its basic subsection does not use the four-year and ten-year thresholds described above.
This matters when a relationship also involves supervision, care, or responsibility for a young person's welfare. The statutory definition of a position of trust appears in §18-3-401 and is broader than a job title alone. A person should not assume that being young, being called a friend, or having only temporary responsibilities settles the issue.
For example, comparing two peers with a student and an adult responsible for that student's supervision requires more than comparing birthdays. The responsibility itself may be legally relevant. Whether a particular arrangement meets the statutory definition depends on its facts.
The useful principle is narrow: an age-gap calculation cannot substitute for checking a separate position-of-trust offense. A chart covering only §18-3-402 will not provide that answer.
What the ten-year threshold does and does not say
A ten-year threshold can sound surprising when detached from its statutory setting. It should not be presented as a recommendation about a relationship, a measure of maturity, or a statement that every fifteen-year-old can consent in every circumstance.
It identifies one element of one age-based provision. Colorado still separately addresses situations involving lack of consent or inability to appraise the nature of the conduct. A person's willingness also does not answer whether an authority-based offense applies.
Consider a sixteen-year-old and someone exactly ten years older. The gap satisfies subsection (1)(e)'s age-difference element. Change the gap to nine years and eleven months and that element is absent. Neither example supports a conclusion about all other statutes without additional facts.
Keeping the legal conclusion this precise helps avoid two opposite mistakes: describing an age bracket too broadly as permission, or treating every adult-minor relationship as if the same age-based offense necessarily applies.
Why an older state memorandum is not enough
Colorado Legislative Council published a useful age-of-consent memorandum in 2018. It explains the four-year and ten-year framework, and older articles frequently rely on it. Its date matters, especially when an article discusses offense classification or punishment.
The current §18-3-402(3) classifies conduct under subsection (1)(e) as a class 6 felony. An older explanation that describes that category as a misdemeanor should not be repeated as current law. The age brackets can remain familiar while other consequences change.
This article uses the legislature's 2026 code edition for the operative framework. The historical memorandum is useful background, but it is not the final authority for a current event. For an older event, the applicable version and any relevant effective-date provisions require their own review.
The same method works beyond Colorado: verify both the substantive rule and the consequence. An unchanged headline about an age of consent does not establish that every paragraph beneath it remains accurate.
A practical way to organize the facts
Before relying on an online explanation, write down four separate items: both dates of birth, the date of the event, the state where it occurred, and the legal category of conduct being discussed. Add any facts about supervision, care, employment, or other responsibility between the people involved.
Keep dating history in a separate column. When the relationship began may explain the situation, but these age-based provisions focus on ages at the conduct. Meeting before an eighteenth birthday does not freeze either person's legal status.
If the question involves images or online messages, identify that separately too. The sexual-contact and penetration provisions discussed here do not by themselves resolve laws governing creation, possession, or distribution of sexual images.
For a real allegation, a Colorado lawyer can review the precise statutory subsection, the version in effect, and the evidence needed for each element. The most useful question to bring is specific: which element or defense does this fact change? That approach produces a more reliable answer than asking whether the relationship is simply “covered by Romeo and Juliet.”
Official sources and further reading
- Colorado General Assembly — 2026 Revised Statutes, including Title 18
- Official 2026 Title 18 text — §§18-3-401, 18-3-402, 18-3-405, and 18-3-405.3
- Colorado Legislative Council — historical age-of-consent memorandum