  We present new Period-Age (PA) and Period-Age-Color (PAC) relations for
fundamental and first overtone classical Cepheids. Current predictions rely on
homogeneous sets of evolutionary and pulsation models covering a broad range of
stellar masses and chemical compositions. We found that PA and PAC relations
present a mild dependence upon metal content. Moreover, the use of different PA
and PAC relation for fundamental and first overtone Cepheids improves the
accuracy of age estimates in the short-period (log P < 1) range (old Cepheids),
because they present smaller intrinsic dispersions. At the same time, the use
of the PAC relations improves the accuracy in the long-period (log P >= 1)
range (young Cepheids), since they account for the position of individual
objects inside the instability strip. We performed a detailed comparison
between evolutionary and pulsation ages for a sizable sample of LMC (15) and
SMC (12) clusters which host at least two Cepheids. In order to avoid deceptive
uncertainties in the photometric absolute zero-point, we adopted the
homogeneous set of B,V,I data for clusters and Cepheids collected by OGLE. We
also adopted the same reddening scale. The different age estimates agree at the
level of 20 % for LMC clusters and of 10 % for SMC clusters. We also performed
the same comparison for two Galactic clusters (NGC6067, NGC7790) and the
difference in age is smaller than 20 %. These findings support the use of PA
and PAC relations to supply accurate estimates of individual stellar ages in
the Galaxy and in external Galaxies. The main advantage of this approach is its
independence from the distance.
