Surgical devices are provided having power-assisted or fully powered jaw closure. The devices herein generally include a handle portion, an elongate shaft, and an effector having first and second jaws configured to engage tissue. A motor and one or more compression springs can be operatively coupled, and activation of the motor can compress the spring(s) to reduce the amount of user supplied force to compress tissue between the jaws. In some embodiments, the devices can be configured to regulate an amount of compression applied by the jaws prior to, during, and/or after cutting of the tissue to promote hemostasis. For example, the devices can include sensors, processors, and/or other components that analyze data indicative of tissue type and tissue load. Based on this feedback, the device can automatically adjust the amount of compression or energy applied to the tissue to seal the tissue.