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

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

1. You reasonably believe it necessary to protect against imminent harm, and
2. 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.

There is usually no duty to retreat from an altercation before defending yourself. However, you typically lose the right of self-defense if you are 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.”

Self-defense is considered an affirmative defense. This means you admit that you committed the crime you are accused of but only because you were lawfully acting out of self-preservation. A successful self-defense argument should result in your criminal charge getting dismissed. In this article, our Denver criminal defense attorneys will address the following key issues regarding Colorado self-defense laws:

• 1. Non-Deadly v. Deadly Force
• 2. Stand Your Ground
• 3. Starting Fights and Mutual Combat
• 4. Defense of Property
• 5. Defense of Others
• 6. “Make My Day”
• 7. Proving Self-Defense
• 8. Common Crimes in Self-Defense Cases
• Frequently Asked Questions

1. Non-Deadly vs. Deadly Force

Under Colorado self-defense law, you can 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 and gets charged with murder. George probably used too much force for a self-defense argument. The punch did not cause serious bodily injury, so there was no reason to justify using deadly force.

In Colorado, 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.¹

Example: Paul pulls a gun on George. George takes out his gun and shoots Paul dead. Since George reasonably believed that Paul was threatening George’s life, George’s use of deadly force was justified. Therefore, George should not be convicted of murder. 

Note that 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 6). However, your ability to use deadly force is at its weakest if you are only defending your property, not your person (discussed below in section 5).

In reality, self-defense cases often fall within gray areas, especially when deadly force is involved. Whenever harm seems imminent, people act on a “fight or flight” instinct without thinking things through. Though as long as your actions were reasonable under the circumstances, a jury should find that you acted lawfully. 

2. 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.

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 dead without trying to get out of the way. Even though Robert could have tried to run away, he was under no legal obligation to. His life was being threatened, so the killing was justified.²

That being said, we advise people to flee danger if they safely can. This way, you never have to face a jury questioning whether the degree of force you used was reasonable under the circumstances. 

3. Starting Fights and Mutual Combat

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

1. You withdraw from the encounter; and
2. You effectively communicate your intent to withdraw; and
3. The other person continues to attack.

If these three things happen, you turn from the initial aggressor into a victim. Only then can you use force in self-defense.

Example: Clyde holds up his shotgun to shoot when he knocks on Ken’s door. When Ken sees the shotgun and draws his own gun to defend himself, Clyde shoots him in the arm. Clyde gets charged with assault.

Here, Clyde cannot claim self-defense since he provoked the fight and never withdrew from the situation. Therefore, he would be convicted of assault. 

In cases of mutual combat where you and another person agree to fight, Colorado law does not allow you to claim self-defense if you injure or kill the other person. This is because you knowingly walked into a situation where someone was likely to get hurt.³

Example: William challenges Bertram to a duel. Bertram agrees. Bertram wins the duel by shooting at William. If Bertram is charged with attempted murder, Bertram cannot then claim self-defense.

We often see these situations when people, typically men, get into a verbal altercation at a bar and mutually agree to “take it outside.” Physical violence is unlawful unless it is part of a licensed sporting event or training session, so you cannot use self-defense as a “get out of jail free card” if someone gets hurt. 

4. 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.

Example: Johnny snatches Claire’s purse. Claire sprays mace at him and takes the purse back. Here, Claire is likely justified in using non-lethal force to retrieve her property. Claire should not be convicted of assaulting Johnny. 

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

In our experience, the bar for defense of property is higher than for defense of people. This makes sense since property damage is less important than physical damage to a person, and courts would prefer that property-related disputes be remedied with words rather than violence. 

Ultimately, courts judge whether your behavior is reasonable under the circumstances. For example if a trespasser goes on your yard and seems to pose no threat, it may be reasonable to take them by the arm and push them out if they refuse to leave on their own.

However, courts would probably find it excessive to punch a trespasser unless they attacked you first. If you do attack first, the trespasser can even stand their ground and attack you back with proportional force.⁴ 

5. Defense of Others

Under Colorado law, 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 themselves.

We find that “defense of others” cases are often the most complicated. Fears and tempers are especially heightened when your loved ones are being threatened. Plus since there are more people involved than just you and the assailant, you may not fully know what is going on: You may not know who is physically where and when.

Fortunately, the law recognizes this uncertainty. It allows you to act on how things seem to be rather than what actually is. As with self-defense, defense of others is justified as long as you acted reasonably under the circumstances.⁵

6. “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:

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

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 you stronger rights to self-defense in your homes than anywhere else. Even if the intruder meant no harm, the Make My Day law protects you from both criminal and civil liability as long as you reasonably believed the intruder meant to cause harm.

How “Make My Day” 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.

When we raise “Make My Day” claims for our clients, we gather all the evidence available that indicates the intruder was up to no good. Examples include:

• Ring or ADT video of the intruder trying to break into the home, and/or
• Any burglary tools the intruder was carrying, and/or
• Any weapons the intruder was carrying.

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.⁶

If you suspect an intruder is on the premises but not yet inside your dwelling, contact the police right away. There is often an officer within a few blocks who can speed over and prevent you from having to exercise your “May My Day” rights. 

7. Proving Self-Defense

If you wish to claim self-defense in your Colorado criminal case, you do not actually have to prove you acted in self-defense. As long as the judge agrees there is “credible evidence” you acted in lawful self-defense, the prosecution bears the burden to prove beyond a reasonable doubt that you did not act in self-defense. 

The prosecution will typically try to disprove a self-defense claim by arguing to the jury that you acted unreasonably. For your self-defense claim to succeed, it is not enough that you personally believed that you (or others) were in imminent danger and that you fought back with proportional force: The jury has to believe they might have acted the same way in your shoes.

You can still win on a self-defense claim even if your “reasonable belief” was wrong in hindsight. What matters is whether an ordinary person would deem your actions reasonable under the circumstances as you knew them at the time.⁷

Evidence of Self-Defense

Even though prosecutors have the burden to disprove self-defense once it is raised, we still introduce as much evidence as possible to support our clients’ self-defense claims. 

When we build a self-defense case for our clients, common evidence we gather 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.

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 your Colorado criminal charges should be dismissed.

We frequently claim self-defense when 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.
• 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 assert your rights later.

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.⁸

See our related article about citizens’ arrests in Colorado.

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.

In our experience defending violent crime cases, the biggest disputes usually are not about what happened, but whether the defendant’s belief that deadly force was necessary was objectively reasonable. Prosecutors often argue that the danger had already passed or that a lesser amount of force would have been sufficient.

Video footage, eyewitness testimony, and forensic evidence frequently determine how a jury views the reasonableness of a defendant’s actions.

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.

From what we have seen, these cases often hinge on whether there is convincing evidence that the defendant truly ended the confrontation before using force. Surveillance video, text messages, 911 recordings, and witness testimony can all be critical in showing whether someone actually withdrew from the fight or instead continued the confrontation.

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.

Many people we talk to mistakenly believe that “Stand Your Ground” means they can use force whenever they feel threatened. That is not the law. Even though there is generally no duty to retreat, prosecutors may still closely examine whether the defendant reasonably believed force was immediately necessary under the circumstances.

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.

In practice, people often overestimate the amount of force the law allows them to use to protect their property. A theft that does not threaten anyone’s safety rarely justifies serious force, and cases can quickly shift from the property crime itself to whether the property owner’s response was lawful.

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.

In our experience, this issue frequently turns on whether the confrontation involved more than words. Juries often consider the person’s actions, body language, distance, prior threats, and whether they appeared capable of immediately carrying out the threat. The totality of the circumstances—not just the words spoken—usually determines whether a claim of self-defense succeeds.

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