A utility knife includes a shell including first and second shell bodies releasably assembled together. A compartment is defined by the first and second shell bodies. A channel is defined at a distal end of the first shell body of the shell and is disposed outside of the compartment. A blade carrier assembly releasably engages with a blade and includes a seat movably received by compartment of the shell. The blade carrier assembly is operably movable to a first position in which the blade is in a retracted position and not extending out of the shell and, to a second position in which the blade is in an exposed position and extending out of the shell. The blade carrier assembly in the second position thereof is also guided by the channel.