Methods and systems are disclosed herein for accurately calculating battery consumption in a wireless field device. The total current consumed by a radio board associated with a wireless field device can be determined based on the sum of the current consumed as a result of particular events occurring at the radio board. The current consumed by a sensor board of the wireless field device can then be averated with respect to particular type of sensor. The current consumed by the radio board and the current consumed by the sensor board in the wireless field device can be combined to calculate a predictive value indicative of a remaining life of a battery associated with the wireless field device.