Transient voltage overshoot is a common phenomenon in wide bandgap (WBG) power semiconductors due to high frequency and fast switching applications. An application driven repetitive transient off-state overvoltage datasheet specification is desired for design engineers. In this work, a 1% duty-cycle-based overvoltage specification is proposed by estimating the total lifetime before the dynamic RDS( on) shift exceeds 20% increase to its initial value under 120% of VDS, Max continuous bias and 75∘C junction temperature. This 1% duty cycle suggests that GaN devices can withstand a 1% duration of each switching period repetitively over 25 years of continuous switching.