Was given several nice new fly lines. Problem is they are unmarked as to size. They are floating weight forward lines - how do I tell them apart???

Get a fly line scale and measure the first 30'

If you know someone who reloads ammunition, one of those scales will work as well. The trick is to coil the line up and tie it off with a twisty tie (weigh it separately and subtract if you're going to be exact about it) so that it will fit in the little powder vessel.

Is there a chart that tells me what size/number the weights correspond to??

I don't think these numbers are absolute, but the chart at the bottom of this page seems to be a pretty good guideline.

Drill down in the Common Cents System as well. It might be more information than you were looking for but its a great piece of information. Might find yourself building rod gauges!

Aw, shucks, George, you're gonna make me blush.

Here's everyone's useless trivia fact for today: There are 7,000 grains in a pound and 437.5 grains per ounce. Grains is small.

TX, you beat me to the chart by seconds so I deleted my post - good work as usual ...

At one time BassPro gun dept. would weigh fly lines for 'ya .... might be busy this tiem of year tho.

Reloading scale is easiest - I keep one on my desk - handy if you are a "fly-line butcher" ....

Hey, that gives me an idea - I've been wanting to experiment with a triangle taper and have some old heavy flies lines to work with...

I wish you hadn't deleted yours, George, it had an important clarification to mine: weigh the first 30 feet of line. Mine makes it sound like you coil up all of it before you weigh it.