I'm not sure if it's just me lol, but it seems to be hard to check a push rod length and cross reference your size to buy a new one. I know Comp Cams and the like make an adjustable rod, but I had a load of rods from past project and didn't know how to measure them so they would correspond to say Comp or Trend.
So I made some end caps that fit over the end of the rods that sit on the working radius of the ball, so now it's a simple measure between calipers. Seems to work really well and repeats to .002 from known rods.

pushrods are measured from end to end,when you order pushrods the total length is what they will make.

Some companies do it different. I simply send them the adj pushrods so they can measure them and do the math their way . Super cheap 2-3day shipping thru USPS anyway. they send them back with the new pushrods.

through the years i have ordered hundreds of pushrods and they always want end to end length.if one does not have a means to measure the length maybe a machine shop could do it for them.

I based my checker on how Comp and trend measure there rods, I found out the hard way that there rod lengths are (gauge lengths) and not end to end lol. My end caps are machined to fit over the rod and is on the cord of the ball that comp and trend used. I made them plus .250" on each end. So you just subtract .500" from your caliper measurement and this will give you a (gauge length).

when i order from trend i give them end to end ,they know the radius a bbc pushrod uses.no need to overthink the simple process but do it however you think is right.

I just ordered a set of Manton pushrods. I set up length with adjustable pushrod and measured with a veneer. Set came just what I ordered.

I use adjustable pushrod to get proper length and then measure it with a measuring tape.

Less high tech than most of you.

Russ