A method of correcting a downhole speed of a tool string moving in a wellbore. In some implementations, the method includes obtaining a downhole tool speed with an accelerometer, moving the tool string past at least two casing collars, calculating the average tool speed over the interval between collars, and comparing the downhole tool speed as calculated using the data from the accelerometer to the average tool speed calculated based on the time and the interval between the casing collars, determining a correction factor, and determining a corrected downhole tool speed. A system includes a casing collar locator, an accelerometer, and a processor adapted to compare the downhole tool speed calculated using data from the accelerometer to the average downhole tool speed calculated using the time and casing collar location, determine a correction factor and determine a corrected downhole tool speed.