The impact of hybrid automatic repeat request (HARQ) retransmission on Voice over Long Term Evolution (VoLTE) cell capacity is investigated in a single LTE cell. An analytical model is proposed to estimate the cell capacity in terms of number of users. The effect of HARQ on cell capacity is investigated and it provides solution to derive transmission parameters in a given radio condition to estimate VoLTE cell capacity. This model may be further useful while estimating call blocking performances and to design efficient Call Admission Control for next generation cellular mobile networks.