What is .3437 inches in fraction?

.3437" is the thickness of some plywood siding available. For homeowners, trying to figure out what that actually means on a ruler is the reason for the OP question.

.3437" is just about 11/32" which is almost 3/8" (.375"). Not 1/4" plywood, not 1/2", and not truly 3/8", but 3/8" is the close enough for a homeowner with a tape measure.

Now, for a cabinet maker... well, they aren't asking the question.