Abstract: A string trimmer includes: a housing; a line container, configured to accommodate a trimmer line, and an end of the trimmer line extending out of the line container; a motor, configured to drive the line container to rotate to perform cutting work; a start switch, configured to generate a start signal according to an operation of a user, to control the motor to start or stop; a release mechanism, capable of selectively releasing the trimmer line, to increase the length of the trimmer line that has extended out of the line container; and a calculation unit, configured to respond to a release signal to calculate the usage and/or remainder of the trimmer line. In the embodiments of the present disclosure, the calculation unit configured to calculate the usage and/or remainder of the trimmer line is disposed in the string trimmer.