Fan y Big (or Fan y Bîg on Ordnance Survey maps), /væn.ə.ˈbiːɡ/, is a subsidiary summit of Waun Rydd in the Brecon Beacons National Park, in southern Powys, Wales. At 719m, Fan y Big lies at the western tip of the Gwaun Cerrig Llwydion plateau. Its name translates as 'peak of the bill' - perhaps in allusion to its striking pointed shape, as seen from some directions. The summit is bare and marked with a cairn, which stands on the edge of its precipitous western face.