The winding channel is 30 km (18 miles) long and about 2 km (11.2 miles) wide, narrowing to 750 metres (2,250 feet) at Rumeli Hisare.
The channel is 30km long, 2km wide, and narrows at Rumeli Hisare.
The channel is 100km long, 5km wide with its narrowest point at 2km.