A study was undertaken to develop a user‐friendly software tool (ValT) for validation of predictive models based on the acceptable prediction zones (APZ) method. ValT was developed in Excel and was demonstrated using a newly developed growth model for Salmonella and chicken skin. The model provided acceptable predictions when the proportion (p) of residuals in the APZ was ≥0.70 and there were no local prediction problems. The pAPZ were 0.97 for dependent data (n = 360), 0.93 for interpolation data (n = 160) and 0.88 for extrapolation data (n = 180) to kosher chicken skin. There were no local prediction problems, and all sets of data satisfied the test data criteria of the APZ method. Thus, the model was successfully validated for interpolation and for extrapolation to kosher chicken skin. It is hoped that the new software tool will make it easier to validate models using the APZ method.