So lately I've been obsessed with finding the best fishing line. I always fish in some sort of current so I try to use the thinnest line that still has good strength. Over the last year I did many tests in my basement and was shocked on how companies advertise a certain diameter of line and strength, but it rarely reflects reality. I came across some videos on YouTube of this site called " The Line Laboratory ". This is by far the best I've seen. What are your favorite reference sites ?

Many years ago I was involved in some world record fishing attempts where we used a line testing apparatus to test fishing lines.  At the time, most of our line was monofilament.  As you discovered most fishing line is not what it is advertised.  Frequently the line tested 20-30% higher than the label stated.  It wouldn't surprise me if the fudge factor on line diameter was equally flawed.

 As far as monofilament I find that the line breaks pretty much as advertised, compare to most braid break 50-80% higher than advertised. But as for the diameter, they pretty much all say that their line is thinner than they really are

There is standardized test procedure or method to use to evaluate line strength, both tensile break and impact.

The rate force is applied needs to be established for example.

Measuring Braid diameter needs to use a die gauge or cross section because it isn’t round. Most extruded monofilament line varies in both roundness and diameter every few feet.

Quality control is higher and more reliable diameters with line made in Japan.

Tom