If you're using an elastic fabric, purchase material that's at least 1.2 m (3.9 ft) in length and 1.4 m (4.6 ft) in width. If your dress is made with silk or another non-elastic fabric, your fabric must be 2.4-2.5 m (7.8-9.2 ft) long and 1.4 m (4.6 ft) wide.