A method of absolute calibration of electrodynamic seismic sensors by single-sensor displacement is theoretically justified. It is shown that the method can be implemented using simple mechanical devices and a recording system. The required mathematical processing of the step-test impact can also be carried out using only standard software on any modern PC. A practical implementation of the method is shown by the example of calibration of a 10 Hz geophone. Features of the test technology and the mathematical processing of the obtained record are presented. The method is recommended for the calibration of sensors (velocimeters) with natural frequencies from 0.5 to 30 Hz.