  The ever-growing number of large spectroscopic survey programs has increased
the importance of fast and reliable methods with which to determine precise
stellar parameters. Some of these methods are highly dependent on correct
spectroscopic calibrations. The goal of this work is to obtain a new
spectroscopic calibration for a fast estimate of Teff and [Fe/H] for a wide
range of stellar spectral types. We used spectra from a joint sample of 708
stars, compiled from 451 FGK dwarfs and 257 GK-giant stars. We used
homogeneously determined spectroscopic stellar parameters to derive temperature
calibrations using a set of selected EW line-ratios, and [Fe/H] calibrations
using a set of selected FeI lines. We have derived 322 EW line-ratios and 100
FeI lines that can be used to compute Teff and [Fe/H], respectively. We show
that these calibrations are effective for FGK dwarfs and GK-giant stars in the
following ranges: 4500 K < Teff < 6500 K , 2.5 < logg < 4.9 dex, and -0.8 <
[Fe/H] < 0.5 dex. The new calibration has a standard deviation of 74 K for Teff
and 0.07 dex for [Fe/H]. We use four independent samples of stars to test and
verify the new calibration, a sample of 56 giant stars, a sample composed of
Gaia FGK benchmark stars, a sample of 36 GK-giant stars of the DR1 of the
Gaia-ESO survey, and a sample of 582 FGK-dwarf stars. We also provide a new
computer code, GeTCal, for automatically producing new calibration files based
on any new sample of stars.
