An apparatus for estimating bio-information, may include: a sensor part having a photoplethysmography (PPG) sensor configured to measure a PPG signal from an object of a user, and a force sensor configured to measure a contact force between the object and the PPG sensor; an output interface, which before the PPG signal is measured, is configured to output first guide information indicating a predetermined number of times the user is required to touch the sensor part, and second guide information indicating a number of times that the sensor part has been touched since the first guide information is output; and a processor configured to estimate bio-information of the user by using the PPG signal based on the number of times that the sensor has been touched since the first guide information is output, corresponding to the predetermined number of times the user is required to touch.