Convert an amount in lineal metres to square metres using the lineal metre amount and the board's width in millimetres. You can use this, amongst other things, if you are looking to buy some boards in lineal metres and need to know how many square metres these boards will cover.

Formula

Sqm = Lm * (Bm/1000)

where Sqm = square metres
Lm = lineal metres
Bm = actual width of the board in millimetres

Example

255 lineal metres of board
Actual board width 235 millimetres

Convert the 235 mm to metres by dividing by 1000;

235  ÷  1000  = 0.235

235 millimetres equals 0.235 metres.

Multiply the two amounts together to get the sqaure feet;

255  *  0.235  =  59.925

255 lineal metres of board covers 59.925 square metres.