Where are banjo scales measured from?

[The Moose]

This question has been bugging at me for a while and I'm sure it's somewhere on the internet but I just can't find it!

Are banjo scales measured from the moveable bridge or the tailpiece? I'd assume it's the bridge but I've never had a chance to play the banjo or similar bridged instruments and I don't know if the bridge actually changes the length of the vibrating string :L I assume it does but I'm still not sure...

The reason I ask is I am thinking of taking a 28" scale plectrum banjo and having a bash at converting it into a (very) short scale bass (the Ibanez Mikro is 28", so it's not impossible :P) and I know I'll need to get a custom nut and bridge to fit the fat strings I'll need.

Any banjoists (is that the right term? D: I'm VERY new to the whole banjo world) who can help me out? Thanks

[AnchorHoy]

Quick and easy way to determine scale length of most fretted instruments:

Measure distance between the nut and the 12th fret. That measurement x2 = scale length

Bridge position can often be an unreliable guide to scale length, because of compensation issues

[JtheJazzMan]

The vibrating length is between the open nut and bridge, and since the banjo has a fixed bridge you can measure it from there.

[MalcolmAmos]

Kinda off topic, however. Long time ago banjos were made from guards and gopher skins. How did they know where the frets should go? Well....... same way they learned how to plow; by watching Pa plow and did likewise. I bet they measured Pa's old banjo when they made them one.

My $100 fiddle does not have frets, where do I put my fingers for specific notes. The instructions told me to go up the neck a certain length and put a piece of tape there so I could remember where that note is fretted. Being me - I then went one step further - I attached my acoustic tuner and when I got the note dead on I adjusted the piece of tape.

For dead on check yourself with a tuner.