  It is now possible to theoretically calculate the gravitational-wave signal
from the inspiral, merger and ringdown of a black-hole-binary system. The late
inspiral, merger and ringdown can be calculated in full general relativity
using numerical methods. The numerical waveforms can then be either stitched to
inspiral waveforms predicted by approximation techniques (in particular
post-Newtonian calculations) that start at an arbitrarily low frequency, or
used to calibrate free parameters in analytic models of the full waveforms. In
this review I summarize the status of numerical-relativity (NR) waveforms that
include at least ten cycles of the dominant mode of the GW signal before
merger, which should be long enough to produce accurate, complete waveforms for
GW observations.
