Adaptive acoustic pressure estimation is provided in medical ultrasound. The responses of tissue of a specific patient at different frequencies (e.g., linear and non-linear responses) are measured. The responses are used to determine the acoustic pressure. The measurement in a specific patient adapts the estimate to the patient. The acoustic pressure for the desired locations is determined in order to set the transmit power to the desired level, such as for contrast agent imaging with high SNR but with limited destruction of the contrast agents or to provide the desired thermal dose the acoustic therapy.