The simple offset formula (or the 45 degree offset formula) is used to calculate where you should be cutting your pipe. Essentially, you are simply multiplying your offset by 1.414 to determine the cut point. Even using this formula however, you must still take into account the fact that you will be adding fittings to the pipe and will need to adjust your measurements accordingly. “Simple” right?
1.) Picture the pipe entering and leaving the box, and if necessary make an illustration with pen and paper. Find the height of the box (called the rise) as well as the width of the box (called the offset). In this case, let’s say the rise is 5 inches and the offset is 10 inches.
2.) Multiply the offset by itself, and the rise by itself, and add these two numbers together. In the example, 5 x 5 = 25 and 10 x 10 = 100. Therefore, 25 + 100 =125.
3.) Taking the square root of this number will yield your rolling offset. In this case, the square root of 125 = 11.18 inches.