The need to support various recognition applications on energyconstrained mobile computing devices has steadily grown. Exploiting common characteristics of recognition algorithms, a very energy-efficient multiplier that can support a runtime trade-off between computational accuracy and energy consumption is proposed. Compared to a precise multiplier, the proposed multiplier consumes 11.6×-3.2× less energy per multiplication while achieving 82-99% of the computational accuracy with negligible negative impact on recognition accuracy for three different recognition applications.