A wireless power transmitter comprising: a power conversion unit configured to transmit, to a wireless power receiver, wireless power generated based on magnetic coupling in a power transfer phase; and a communication/control unit configured to: receive, from the wireless power receiver in a first operating mode, a first received power packet related to power calibration, wherein a mode value included in the first received power packet is 1, receive after the first received power packet, from the wireless power receiver in the first operating mode, a second received power packet related to power calibration, wherein a mode value included in the second received power packet is 2, construct a first power calibration curve based on a received power value included in the first received power packet as a first calibration data point of the first power calibration curve and a received power value included in the second received power packet as an additional calibration data point of the first power calibration curve, receive after the second received power packet, from the wireless power receiver in a second operating mode, a third received power packet related to power calibration, wherein a mode value included in the third received power packet is 1, receive after the third received power packet, from the wireless power receiver in the second operating mode, a fourth received power packet related to power calibration, wherein a mode value included in the fourth received power packet 2, and construct a second power calibration curve based on a received power value included in the third received power packet as a first calibration data point of the second power calibration curve and a received power value included in the fourth received power packet as an additional calibration data point of the second power calibration curve. a power conversion unit configured to transmit, to a wireless power receiver, wireless power generated based on magnetic coupling in a power transfer phase; and a communication/control unit configured to: receive, from the wireless power receiver in a first operating mode, a first received power packet related to power calibration, wherein a mode value included in the first received power packet is 1, receive after the first received power packet, from the wireless power receiver in the first operating mode, a second received power packet related to power calibration, wherein a mode value included in the second received power packet is 2, construct a first power calibration curve based on a received power value included in the first received power packet as a first calibration data point of the first power calibration curve and a received power value included in the second received power packet as an additional calibration data point of the first power calibration curve, receive after the second received power packet, from the wireless power receiver in a second operating mode, a third received power packet related to power calibration, wherein a mode value included in the third received power packet is 1, receive after the third received power packet, from the wireless power receiver in the second operating mode, a fourth received power packet related to power calibration, wherein a mode value included in the fourth received power packet 2, and construct a second power calibration curve based on a received power value included in the third received power packet as a first calibration data point of the second power calibration curve and a received power value included in the fourth received power packet as an additional calibration data point of the second power calibration curve. receive, from the wireless power receiver in a first operating mode, a first received power packet related to power calibration, wherein a mode value included in the first received power packet is 1, receive after the first received power packet, from the wireless power receiver in the first operating mode, a second received power packet related to power calibration, wherein a mode value included in the second received power packet is 2, construct a first power calibration curve based on a received power value included in the first received power packet as a first calibration data point of the first power calibration curve and a received power value included in the second received power packet as an additional calibration data point of the first power calibration curve, receive after the second received power packet, from the wireless power receiver in a second operating mode, a third received power packet related to power calibration, wherein a mode value included in the third received power packet is 1, receive after the third received power packet, from the wireless power receiver in the second operating mode, a fourth received power packet related to power calibration, wherein a mode value included in the fourth received power packet 2, and construct a second power calibration curve based on a received power value included in the third received power packet as a first calibration data point of the second power calibration curve and a received power value included in the fourth received power packet as an additional calibration data point of the second power calibration curve.