Big. If you measure by length (approx 1 metre) and wingspan (over 2 metres), they're the third largest eagle in the world on both those measurements. They're lightweights though despite the size, not in the top 5 on weight. Had the pleasure one afternoon of tail-gating one in a car. It had lifted off from eating some roadkill at the side of the road and flew along just above the bonnet for a good distance before veering off. Wingspan was wider than the car, amazing sight.
(The Wedge-tailed Eagle is where my username here comes from actually - the latin name for the species is Aquila audax.)
From experience looking out at Splash Point, when the peregrine falcons fly around Seaford Head the seagulls run for cover!