How do we measure golf club length?
For most clubs we measure length by putting club in approximate playing position and then putting a long (48 inch) metal ruler firmly under the club head and measure to the end of the grip, or otherwise known as "playing length".
See red line below, that is where the ruler would be placed
How do we measure putter length?
For putters we measure the same as above, except the ruler is set in line with the center (or alignment line) of the putter head. See picture on the right below:
Why do we bother telling you how we measure club length? Because different ways of measuring give different results, and because not all manufacturers measure exactly the same way.