Computational radio frequency identification (CRFID) tags sense the environment and transmit the sensed data using the received energy from readers. To operate CRFID tags, both information and energy need to be delivered appropriately. Simultaneous wireless information and power transfer (SWIPT) can be useful for such CRFID applications. However, in a SWIPT network, undesired signals may be harmful or helpful from the information decoding or energy harvesting perspective. In this letter, we focus on the performance of joint information and power transfer for CRFID tags. We model a SWIPT-enabled CRFID network with the Poisson point process (PPP). The joint probability for simultaneously receiving both information and power is derived using the properties of the PPP, which determines the optimal transmission probability and the optimal power splitting factor in a SWIPT-enabled CRFID network.