AbstractEssential Work of Fracture (EWF) analysis was used to study the fracture toughness of a PETG film. In the study of the gauge length (Z) effect on the specific essential work (we) using Z = 50, 100, 150, 200 and 250 mm, it is observed that we is Independent of gauge length, except that a slightly lower we value was measured for Z = 50 mm. Interestingly, for specimens with long gauge lengths (Z ≥ 150 mm in this study), brittle fracture occurred. The minimum ligament length at which ductile/brittle transition took place was observed to decrease with increasing gauge length. There is a small strain rate effect on we with loading rates less than 1 mm/min. But with higher loading rates, we showeld no strain rate sensitivity.