We present the error budget for the calibrated and geolocated spectra of the MIPAS limb sounder which flew on the ENVISAT satellite from 2002 to 2012. The impact of the different error sources on the spectra is characterized in terms of spectral, vertical, and temporal correlation. The radiometric error is in the order of 1 to 2.4 %, the spectral accuracy is better than 0.3 ppm, and the line of sight accuracy at the tangent point is around 400 m. All errors are well within the requirements.