The present disclosure is directed to a device and method for lid angle detection that is accurate even if the device is activated in an upright position. While the device is in a sleep state, first and second sensor units measure acceleration and angular velocity, and calculate orientations of respective lid components based on the acceleration and angular velocity measurements. Upon the device exiting the sleep state, a processor estimates the lid angle using the calculated orientations, sets the estimated lid angle as an initial lid angle, and updates the initial lid angle using, for example, two accelerometers; two accelerometers and two gyroscopes; two accelerometers and two magnetometers; or two accelerometers, two gyroscopes, and two magnetometers.