It depends on the density and depth. Your topsoil supplier can probably tell you.
If a 40 lb bag is about 1 ft3, then 1.56 m3 will be about 1 metric ton. If you spread it to a depth of 10 cm, that will cover about 15.6 m2.
If a 40 lb bag is about 1 ft3, then 1.56 m3 will be about 1 metric ton. If you spread it to a depth of 10 cm, that will cover about 15.6 m2.