How strong is an EF1 tornado?

There is no given size for an EF5 tornado as ratings are based on wind estimates derived from damage.

An EF5 tornado has estimated winds over 200 mph (322 km/h). Typical EF5 damage includes houses wiped clean off their foundations and large, well built structures completely leveled.

EF5 tornadoes have been recorded at sizes ranging from 60 yards (55 meters) to over 2 miles (3.2 kilometers) wide. Most EF5 tornadoes, though, are over 1/4 mile (0.4 kilometers) wide.