A sensor calibration method is disclosed. The method includes applying thermal energy to a fabrication chamber of an additive manufacturing apparatus to raise a temperature of a surface within the fabrication chamber to a first surface temperature; measuring, using a first sensor to be calibrated, the first surface temperature; measuring, using a second sensor, the first surface temperature; applying thermal energy to the fabrication chamber to raise a temperature of the surface to a second surface temperature; measuring, using the first sensor, the second surface temperature; measuring, using the second sensor, the second surface temperature; determining, using a processor, based on the first and second surface temperatures measured using the first sensor and on the first and second surface temperatures measured using the second sensor, an offset calibration to be applied to measurements obtained using the first sensor; and applying the offset calibration to measurements obtained using the first sensor. An additive manufacturing apparatus and a machine-readable medium are also disclosed.