Colorado Self-Defense Laws - When can I use force legally?

Colorado self-defense law permits you to use physical force to defend yourself or others if:

You reasonably believe it to be necessary to protect against imminent harm, and
You use only the degree of force appropriate for the situation.

For example if the person you are arguing with starts punching you, you can hit back. If that person starts wielding a gun, knife, or other deadly weapon against you, you could even use deadly force against them.

Furthermore, there is usually no duty to retreat from an altercation before defending yourself. To have the right of legal self-defense, however, you typically cannot be the initial aggressor.

The law is clearly stated in Colorado Revised Statute § 18-1-704:

“…a person is justified in using physical force upon another person in order to defend himself or a third person from what he reasonably believes to be the use or imminent use of unlawful physical force by that other person, and he may use a degree of force which he reasonably believes to be necessary for that purpose.”

In short, claiming self-defense quietly admits that you committed the crime you are accused of but only because you were acting out of self-preservation. A successful self-defense argument should result in your criminal charge getting dismissed.

Graphic of common crimes where self-defense applies in Colorado, such as murder or assault

In this article, our Denver criminal defense attorneys will address the following key issues regarding Colorado self defense laws:

1. Proving Self-Defense

Proving a self-defense case under Colorado law involves showing:

You reasonably believed that you were about to suffer imminent and unlawful force, and
You reasonably believed that immediate force was required to protect yourself, and
You used a degree of force that you reasonably believed would be necessary to prevent it.¹

Note that a “reasonable belief” is different from a subjective belief:

A subjective belief is something that only you need to have.
A reasonable belief is something that other people would have in the same situation.

A big part of a self-defense argument is convincing the jury that they would have done the same thing you did.

Importantly, a reasonable belief can still be wrong in hindsight.² You do not need to be absolutely certain that you need to use force to defend yourself. Instead, it is enough to show an apparent necessity.³

Example: David gets thrown out of a Christmas party. He said he was hit in the back of the head and heard a bang as he was pushed out the door. He turns and fires three shots into the closed door. These are not reasonable grounds that self-defense was necessary.⁴

Evidence

To successfully argue self-defense, your defense attorney must gather evidence during the discovery process to show the jury your actions were justified and reasonable. Common evidence used to build a self-defense case includes:

Prior threats or aggressive behavior: Showing the alleged victim had a history of threatening you, which helps establish why you had a “reasonable belief” of imminent danger.
Surveillance footage: Pulling video from nearby businesses, doorbell cameras, or street cameras that captured the altercation.
Physical evidence: Using your own medical records or photographs of your injuries to corroborate that you were attacked first or had to defend yourself.
Statements and communications: Subpoenaing text messages, emails, or voicemails sent between you and the other party before, during, or after the incident.
Witness testimonies and police reports: Cross-referencing eyewitness accounts with the initial police investigation to highlight inconsistencies in the prosecution’s story.
Expert testimony: Utilizing forensic experts to recreate the scene, or medical professionals to testify that the trajectory of the force used matches a defensive posture.

2. Force and Deadly Force

You can only use as much force as you reasonably believe is necessary to protect yourself. In many criminal law cases, this means only using as much force as you are being threatened with.

Example: Paul punches George. George takes out a gun and shoots Paul dead. George probably used too much force for a self-defense argument. The punch did not cause serious bodily injury, so there was no reasonableness to justify using a gun.

Deadly force can be used for self-defense if you reasonably believe that:

You are in imminent danger of being killed or sustaining great bodily injury, or
The assailant is committing a burglary and is about to use physical force against the occupant, or
The assailant is committing a kidnapping, robbery, sexual assault, or felony assault.⁵

Your ability to use deadly force is at its peak if you are in your home under Colorado’s “Make My Day” law (discussed below in section 7). It is at its weakest if you are only defending your property, not your person (discussed below in section 5).

3. Stand Your Ground

Colorado is a “Stand Your Ground” state, which means you can defend yourself without retreating from a fight first. It allows you to use reasonable and appropriate force – including deadly force – without withdrawing.⁶

Unlike Colorado’s “Make My Day” law, Stand Your Ground applies outside the home, as well.

Example: The driver of a car is trying to run Robert over. Robert pulls out his gun and shoots the driver without trying to get out of the way.⁷

Stand Your Ground can be a defense for people who are trespassing on someone else’s property if they are facing unlawful force.⁸ Though since property owners can lawfully use force against a trespasser, trespassers might not be able to claim self-defense against them.

4. Starting a Fight

If you started an altercation in Colorado, you can only claim self-defense if:

You withdraw from the encounter, and
Effectively communicate your intent to withdraw, and
The other person continues to attack.⁹

If these three things happen, you turn from the initial aggressor into a victim. This allows you to use force in self-defense.¹⁰

Additionally, self-defense is not an option if you provoked the fight.¹¹ This prevents people from creating an excuse to use self-defense.¹²

Example: Clyde provokes a fight by holding a shotgun when he knocks on Ken’s door. When Ken draws his gun to defend himself, Clyde shoots him.

Self-defense is also not an option if you agreed to fight.¹³

Example: Sir William challenges Bertram to a duel. Bertram agrees. Bertram wins the duel by shooting Sit William. Bertram cannot claim self-defense.

California’s law of self-defense allows you to stand your ground.

5. Defense of Property

You can use force to defend your property in Colorado if the force is reasonable and appropriate to prevent crimes like:

Unlawful trespass and unlawful entry,
Theft,
Criminal mischief, or
Criminal tampering.¹⁴

Example: Johnny tries snatching Claire’s purse. Claire punches him and sprays Mace in his eyes.

Generally, you cannot use deadly physical force in defense of property unless you are keeping someone from committing arson.¹⁵

6. Defense of Others

The defense of a person other than yourself is very similar to self-defense. You can claim defense of others if you think your intervention is necessary to keep them safe.

This usually means you can claim defense of others if they could have claimed self-defense.¹⁶

In many cases involving the defense of others, you do not fully know what is going on. The law recognizes this. It allows you to act on how things seem to be rather than actual knowledge.¹⁷

7. Make My Day

Colorado’s Make My Day law (“force-against-intruders” statute) allows the occupant of a dwelling to use deadly force against an intruder if they reasonably believe the intruder intends to commit a crime or inflict physical force on an occupant “no matter how slight.” Occupants:

Have no duty to retreat and
May “stand their ground” before confronting the intruder, even if there are easy means of escape.¹⁸

Formally entitled The Homeowner Protection Act, the Make My Day law was adopted in Colorado in 1985 under C.R.S. 18-1-704.5. It is Colorado’s version of The Castle Doctrine, a legal principle that people have the right to “absolute safety” while in their homes.

In short, Colorado’s Make My Day law gives people stronger rights to self-defense in their homes than anywhere else. Even if the intruder meant no harm, the Make My Day law protects occupants from both criminal and civil liability as long as they reasonably believed the intruder meant to harm.

How it Works

For the Make My Day law to apply in Colorado, the intruder must have unlawfully entered the home. That does not necessarily mean “breaking in” such as by picking a lot or breaking a window. Merely sneaking in through an unlocked door qualifies as an unlawful entry as long as the intruder was uninvited.

Example: Julie invites Mary over to her house in Denver. They get in a fight, and Julie demands that Mary leave. Mary refuses. Here, Mary did not unlawfully enter the home. Therefore, the Make My Day law does not give Julie the right to use deadly force on her simply for not leaving.

Instead, Julie could call the police to report a trespasser. Or if Mary becomes violent, then Julie could fight back in self-defense, but only to the extent necessary to deflect the threat. Since the Make My Day law does not apply, Julie could not use deadly force unless she reasonably feared Mary would seriously hurt or kill her.

The Dwelling Requirement

Another requirement for Colorado’s Make My Day law is that the intruder is inside the dwelling, which includes everything from houses or rental apartments to trailers or motel rooms. It does not matter whether the occupant is the homeowner, a tenant, a hotel or Airbnb guest, or a house guest.

The Make My Day law does not allow an occupant to kill suspected intruders while they are still outside, such as:

On a porch, balcony, or terrace;
On top of the roof;
In the backyard;
In the common area of an apartment complex;
In the hallway outside of a hotel room; or
Outside of the front door.¹⁹

8. Common Crimes in Self-Defense Cases

If you can show the crime you committed was in lawful self-defense or defense of others, then the criminal charges should be dismissed. In Colorado, self-defense is a frequent strategy for fighting the following allegations:

First-degree murder – This is intentional killing of another person with deliberation and premeditation. It is Colorado’s most serious homicide crime.
Second-degree murder – This is knowingly killing someone else. It is less severe than first-degree murder, which requires premeditation. For second-degree murder, you just need to be aware that your actions are practically certain to cause death.²⁰
First-degree assault – This is intentionally and seriously hurting someone else. It often involves the use of a deadly weapon. It does not, however, involve a fatality.
Second-degree assault – This is intentionally hurting someone. Unlike first-degree assault, the injuries are not severe.
Menacing – This is knowingly using threats or actions to place another person in fear of imminent serious bodily injury or death. No physical touching is necessary.
Domestic violence assault – This is hurting someone you are in an intimate relationship with. Many instances involve fights and violence from both sides.

Note that self-defense is not a valid defense strategy against a charge of resisting arrest by on-duty police. Even if the arrest is unlawful, you are supposed to comply and raise your rights later.²¹

The only times you can claim self-defense in an arrest situation are when the officer was not acting under the color of law (such as off-duty officers or private security guards). If they try to arrest you and you resist, you can argue you were acting in self-defense.²²

See our related article about citizen’s arrests in Colorado.

one man about to punch another man - Colorado self-defense laws do not protect an aggressor

You do not have to withdraw from an altercation before defending yourself under Colorado law.

Frequently Asked Questions

When can I use deadly force to defend myself in Colorado?

You can use deadly force in Colorado when you reasonably believe you are in imminent danger of being killed or seriously injured, when someone is committing burglary and about to use force against you, or when someone is committing kidnapping, robbery, sexual assault, or felony assault. You must reasonably believe deadly force is necessary to protect yourself.

What happens if I started the fight but then tried to defend myself?

If you started or provoked a fight, you can only claim self-defense if you withdraw from the encounter, clearly communicate that you want to stop fighting, and the other person continues to attack you. If you do not meet all three conditions, you cannot use self-defense as a legal argument.

Do I have to try to run away before defending myself?

No, Colorado follows “Stand Your Ground” law, which means you do not have to retreat or run away before defending yourself. You can use reasonable force, including deadly force when justified, without trying to escape first. This applies both inside and outside your home.

Can I use deadly force to protect my property from thieves?

Generally, no. You cannot use deadly force just to protect property like your car or belongings. You can only use reasonable, non-deadly force to stop crimes like theft or trespassing. The only exception is if someone is trying to commit arson – then you may use deadly force to stop them.

Can I use physical force to defend myself against a verbal threat?

Generally, no. A core pillar of Colorado self-defense law is “proportional force”—meaning you can only use a degree of force appropriate for the situation.

Reacting with physical violence to a strictly verbal threat is almost always deemed excessive under the law. To lawfully use physical force, you must have a reasonable belief that the other person is about to use unlawful physical force against you.

Additional Reading

For more in-depth information on self-defense laws, refer to these scholarly articles:

Abused Women Abused by the Law: The Plight of Battered Women in California and a Proposal for Revising the California Self-Defense Law – California Review of Law & Women’s Studies.
Justifying Self-defense – Law & Philosophy.
A Matter of Evidence or of Law – Battered Women Claiming Self-Defense in California – UCLA Women’s Law Journal.
A New Defense for Self-defense – Buffalo Law Review.

Legal References:

Vigil v. People (Colo. 1960) 353 P.2d 82. A self-defense claim is an affirmative defense, and courts look at what a reasonable person would have done under the circumstances. See also, for example, People v. Martin (Colo. App. 2026) No. 22CA1854 (unpublished).
Beckett v. People (Colo. 1990) 800 P.2d 74.
People v. Ellis (Colo. App. 2001) 30 P.3d 774.
C.R.S. 18-1-704 – Use of physical force in defense of a person – definitions.

(1) Except as provided in subsections (2) and (3) of this section, a person is justified in using physical force upon another person in order to defend himself or a third person from what he reasonably believes to be the use or imminent use of unlawful physical force by that other person, and he may use a degree of force which he reasonably believes to be necessary for that purpose.
(2) Deadly physical force may be used only if a person reasonably believes a lesser degree of force is inadequate and:
(a) The actor has reasonable ground to believe, and does believe, that he or another person is in imminent danger of being killed or of receiving great bodily injury; or
(b) The other person is using or reasonably appears about to use physical force against an occupant of a dwelling or business establishment while committing or attempting to commit burglary as defined in sections 18-4-202 to 18-4-204; or
(c) The other person is committing or reasonably appears about to commit kidnapping as defined in section 18-3-301 or 18-3-302, robbery as defined in section 18-4-301 or 18-4-302, sexual assault as set forth in section 18-3-402, or in section 18-3-403 as it existed prior to July 1, 2000, or assault as defined in sections 18-3-202 and 18-3-203.
(3) Notwithstanding the provisions of subsection (1) of this section, a person is not justified in using physical force if:
(a) With intent to cause bodily injury or death to another person, he provokes the use of unlawful physical force by that other person; or
(b) He or she is the initial aggressor; except that his or her use of physical force upon another person under the circumstances is justifiable if he or she withdraws from the encounter and effectively communicates to the other person his or her intent to do so, but the latter nevertheless continues or threatens the use of unlawful physical force;
(c) The physical force involved is the product of a combat by agreement not specifically authorized by law; or
(d) The use of physical force against another is based on the discovery of, knowledge about, or potential disclosure of the victim’s actual or perceived gender, gender identity, gender expression, or sexual orientation, including but not limited to under circumstances in which the victim made an unwanted nonforcible romantic or sexual advance toward the defendant. Nothing in this subsection (3)(d) precludes the admission of evidence, which is otherwise admissible, of a victim’s or witness’s conduct, behavior, or statements.
(4) In a case in which the defendant is not entitled to a jury instruction regarding self-defense as an affirmative defense, the court shall allow the defendant to present evidence, when relevant, that he or she was acting in self-defense. If the defendant presents evidence of self-defense, the court shall instruct the jury with a self-defense law instruction. The court shall instruct the jury that it may consider the evidence of self-defense in determining whether the defendant acted recklessly, with extreme indifference, or in a criminally negligent manner. However, the self-defense law instruction shall not be an affirmative defense instruction and the prosecuting attorney shall not have the burden of disproving self-defense. This section shall not apply to strict liability crimes.
(5) As used in this section, unless the context otherwise requires:
(a) “Gender identity” and “gender expression” have the same meaning as in section 18-1-901 (3)(h.5).
(b) “Intimate relationship” has the same meaning as in section 18-6-800.3.
(c) “Sexual orientation” has the same meaning as in section 18-9-121 (5)(b).
Idrogo v. People (Colo. 1991) 818 P.2d 752.
People v. Willner (Colo. 1994) 879 P.2d 19.
People v. Toler (Colo. 2000) 9 P.3d 341.
Young v. People (Colo. 1910) 107 P. 274 (“a person…may act on such appearances and defend himself, even to the extent of taking human life when necessary, although it may turn out that the appearances were false, or although he may have been mistaken as to the extent of the real or actual danger”).
C.R.S. 18-1-704(3)(b).
Castillo v. People (Colo. 2018) 421 P.3d 1141.
Bush v. People (Colo. 1888) 16 P. 290 and People v. Willner, Supra.
People v. Silva (Colo. App. 1999) 987 P.2d 909.
C.R.S. 18-1-704(3)(c).
C.R.S. 18-1-706.
See Bush v. People, Supra (“…while a man may use all reasonable and necessary force to defend his real and personal estate, of which he is in the actual possession, against another who comes to dispossess him without right, he cannot instantly carry his defense to the extent of killing the aggressor. If no other way is open, he must yield, and get himself righted by resort to the law”).
People v. Silva, Supra.
People v. Silva, Supra.
People v. Toler, Supra. See also People v. Rau (Colo. 2022) 501 P.3d 803.
People v. Cushinberry (Colo. App. 1992) 855 P.2d 18.
People v. Gonzales (Colo. 1996) 926 P.2d 153.
People v. Hess (Colo. 1984) 687 P.2d 443.
People in Interest of JJC (Colo. 1993) 854 P.2d 801.

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Colorado Self-Defense Laws – When can I use force legally?