Lumber For Framing Calculator

The formula this calculator uses

n = ceil(L / s) + 1

L

Wall length, in metres

s

Stud spacing, in metres once converted from millimetres

n

Number of studs, including both ends

h

Wall height, which sets the length of each stud

w

Waste allowance as a decimal

How to check the result by hand

1. 1

   Measure the wall length

   Measure along the wall rather than between finished surfaces, because the plates run the full length and lap at the corners. Record the figure in metres and keep it consistent with the spacing unit you use next.

2. 2

   Divide by the stud spacing

   Six metres divided by six hundred millimetres is ten spaces, provided both are in the same unit. Using metres for the wall and millimetres for the spacing turns a ten space wall into a ten thousand space wall.

3. 3

   Round up and add one

   Round the number of spaces up to a whole number, then add one for the stud at the far end. Ten spaces give eleven studs. Skipping the plus one leaves the wall one stud short at the end.

4. 4

   Add two studs per opening

   Every door or window needs a stud on each side to carry the trimmer and the header. Count the openings and add two studs each, then add the headers separately from heavier stock.

5. 5

   Add the plates and the waste allowance

   Multiply the wall length by three for the plates, multiply the stud count by the stud length, add the two together, and apply the waste allowance. A ten percent allowance is the usual figure for a hand-framed wall.