On Mon, 18 Mar 2013 06:35:05 -0400, Jim Elbrecht
wrote:

I know what size I need-- and I can try these on to see if they work
for me--

But I have 100 or so glasses of varying magnifications and I want to
sort and label them.

Is there an easy/cheap method of measuring magnification?

Web searches are just turning up pages telling me how to figure out
what strength I need. I want to know what strength I *have*.

Thanks
Jim

Some lenses are marked, but you can't see them under normal condition.
Take a flashlight and shine it into the edge of the lens. Outside the
field of vision, you may see the markings. I wore glasses for decades
and one day my eye doctor showed me that.

Rather than sort and label them, put the to good use by donating them
to the Lions Club. They will fit them to a happy recipient someplace
in the world.