The thickness changes and work hardening arising during the forming process are generally ignored in crash analysis. This paper quantifies the effect of the forming process on crash response of a typical car of stamped steel construction using an analytical study. Forming results for fourteen panels of a mediumsized car were calculated using a one-step stamping analysis code. These were imported into the crash model, and crash results compared with and without the forming effects. The time taken to generate the forming data by a variety of methods is quantified, and the trade-off between the time taken and accuracy is examined. An efficient method of importing the forming data into the crash model is presented.