This paper deals with real-world inventory problems considering the natural idle time like weekly off days and daily closure time. So a cost minimization economic order quantity model is developed considering the idle time costs. In this model, the inventory processing time is divided into two parts: opening time and closing time and also weekly off-day are considered. In a crisp model, a constant rate of deterioration is considered. The deterioration rate, demand rate, and other inventory costs are treated as linear symmetric generalized trapezoidal single-valued neutrosophic numbers to make the model more realistic. The neutrosophic average cost has been derived, and then it is De-neutrosophied using the mean interval method. Hence optimal order quantity, optimal closing and opening time have been derived. Finally, a case study is taken into consideration to support the model, and sensitivity analysis is also presented to justify the model.