Colorado’s laws on the use of physical force contain many nuances and exceptions. To help you better understand when and how much physical force you can legally use, take note of the Statutes as noted below:

1. When can I use physical force to defend myself or my property in Colorado?

Colorado law permits you to use physical force to defend yourself or someone else when:

  • You reasonably believe someone is using, or is about to use, unlawful physical force against you or another person, or
  • Someone has unlawfully entered your home and you reasonably believe that such person has committed, is committing, or is about to commit a crime and might use physical force, no matter how slight, against any occupant.

2. How much force can I legally use?

2.1. Self-defense or defense of another person

Section 18-1-704 of the Colorado Revised Statutes is Colorado’s law on the use of physical force in defense of a person. 18-1-704 C.R.S. applies both to self-defense and defense of someone else.

Under 18-1-704 C.R.S., you may use a degree of force which you reasonably believe necessary to protect yourself or someone else from a crime involving the use of physical force.

However, you may use deadly physical force only if:

  • You reasonably believe a lesser degree of force is inadequate, AND:
    • You have reasonable ground to believe — and you do believe — that you or another person is in imminent danger of being killed or of receiving great bodily injury; or
    • The other person is using or reasonably appears about to use physical force while committing or attempting to commit burglary; or
    • The other person is committing or reasonably appears about to commit kidnapping, robbery, or sexual assault.1

Notwithstanding the foregoing, you are not justified in using physical force if:

  • You provoke the use of unlawful physical force by the other person with the intent to cause bodily injury or death to another person; or
  • You are the initial aggressor — except that you may use physical force if you withdrew from the encounter and effectively communicated to the other person your intent to do so, but the other person continued or threatened to use unlawful physical force anyway; or
  • The physical force involved is the result of combat by agreement not specifically authorized by law.2

2.2. Use of deadly physical force against a home intruder – Colorado’s “Make My Day” law

Colorado grants its citizens the “right to expect absolute safety within their own homes.” This is sometimes referred to as Colorado’s “Make My Day” law or “castle doctrine.” Officially it is known as Colorado’s law on the use of deadly physical force against an intruder.

The law on the use of deadly force in Colorado home intrusions is set forth in 18-1-704.5 C.R.S.

18-1-704.5 C.R.S protects you from both criminal and civil liability if you use any degree of force – including deadly physical force – to protect a dwelling under the following conditions:

  • Someone breaks into your home or other dwelling (such as a hotel room),3 AND
  • You have a reasonable belief that such other person has committed a crime in the dwelling in addition to the uninvited entry, or is committing or intends to commit a crime against a person or property in addition to the uninvited entry, AND
  • You reasonably believe that such intruder might use any physical force, no matter how slight, against any occupant.4

2.3. Do I have a duty to retreat under Colorado’s Make My Day law?

Although not expressly set forth in 18-1-704.5 C.R.S., Colorado imposes no “duty to retreat” before you can use deadly force to protect yourself or others in your home or other dwelling — even if a reasonably safe means of escape exists.5 In this respect, Colorado’s Make My Day doctrine is similar to a “Stand Your Ground” law. However, unlike a true Stand Your Ground Law, Colorado’s Make My Day doctrine applies only to dwellings and only to the extent reasonably necessary for self-defense or defense of others.

2.4. Can I use deadly force to prevent someone from trespassing?

You are justified in using reasonable and appropriate physical force as reasonably necessary to prevent or terminate what you reasonably believe to be:

  • The commission or attempted commission of an unlawful trespass by another person, or
  • An attempt by another person to commit theft, criminal mischief, or criminal tampering involving property.

However, you are not entitled to use deadly physical force to defend property that is not a dwelling except:

  • In self-defense or defense of another person, as set forth above, or
  • When you reasonably believe it necessary to prevent what you reasonably believe to be an attempt by the trespasser to commit first degree arson.6