How to measure the size of stainless steel column before blanking

How to measure the size of stainless steel stair handrail before blanking

Measure the dimension from the bottom to the top, and then add the length of 2 elbows. This degree is difficult to grasp. You'd better start from above. Don't finish the size first. Do two steps and you will know which degree to grasp. Or simply lower the length slightly, and then cut off the excess~~as long as the pipe is aligned with the foot of the next stair after the elbow is added.