  With the increased accuracy and angular scale coverage of the recent CMB
experiments it has become important to include calibration and beam
uncertainties when estimating cosmological parameters. This requires an
integration over possible values of the calibration and beam size, which can be
done numerically but increases computation times. We present a fast and simple
algorithm for marginalization over beam and calibration errors by analytical
integration. We also illustrate the effect of incorporating these uncertainties
by calculating the constraints on various cosmological and inflationary
parameters including the spectral index n_s and the physical baryon density
Omega_b h^2, using the latest CMB data. We find that parameter constraints are
significantly changed when calibration/beam uncertainties are taken into
account. Typically the best fit parameters are shifted and the errors bars are
increased by up to fifty per cent for e.g. n_s and Omega_b h^2, although as
expected there is no change for Omega_K, because it is constrained by the
positions of the peaks.
