Introduction: The invention of a lunch box with phase-change materials incorporated to keep food warm throughout work hours is the subject of this paper. Since harmful chemicals render the food unfit for consumption when they come into contact with it, the choice of phase change material is essential. Method: Adopting a healthy lifestyle now includes carrying electronic lunch boxes and ordering takeaways. Nevertheless, utilizing the electric lunch box at work is a bother. Therefore, this study discusses a prototype of a lunch box that has been created and can keep food warm after it has been packed at home for 4-5 hours. The method of preparing the PCM FS65 is discussed and its stability over thermal cycling is analyzed. objective: To synthesize phase change material composite which does not go into liquid state in melting cycle. To understand the thermal stability of the phase change material composite To prove the efficacy of the composite in lunch box for keeping the food warm Result: The thermal resistance of the insulating materials and the quantity of PCM are the two design considerations for the lunch box that have been covered in this study. To explore these, a warm food criterion at a temperature of 45°C has been used. Conclusion: This research article has discussed the ideal PCM weight required for a 5-hour retention time as well as the ideal insulating material to make the least bulky lunch box design.