From Draftsperson.net
FROM

TO

MULTIPLY
BY

square
millimetres

square
inches

0.00155

square
inches

square
millimetres

645.16

square
centimetres

square
inches

0.155

square
inches

square
centimetres

6.452

square
metres

square
feet

10.76

square
feet

square
metres

0.0929

square
metres

square
yards

1.196

square
yards

square
metres

0.835

square
kilometres

square
miles

0.3861

square
miles

square
kilometres

2.59

hectacres

acres

2.471

acres

hectacres

0.4047
