An electronic device may include: an optical sensor configured to emit a reference light to a reference object and detect the reference light reflected from the reference object during calibration, and emit a measurement light to a target object and detect the measurement light reflected from the target object during a measurement; a display; and a processor configured to: when the electronic device is placed on a charger and is in a charging state, perform the calibration of the optical sensor based on the reference light reflected from the reference object; control the display to output guide information for estimating bio-information according to progress stages of the measurement after charging of the electronic device; and estimate the bio-information based on a light quantity of the measurement light that is reflected from the target object, and a light quantity of the reference light reflected from the reference object.