EEG latency to second transformation formula?

Hi all! I'm working on a study have both EEG and behavioral data. Due to an unexpected data collection mistake in Psychopy, I have to use EEG data to calculate behavioral performance for my project. I'm using EEGLab.I need to transform EEG. event. latency output to seconds in order to figure the reaction time (RT). Does anyone know the formula of tranforming latency to seconds? Thank you so much!