Since this kind of question was posted here on SOL more then once - "**how much of 30# braid can I put on a spool rated at 205 yards with 12# mono. What if 20# or 65#?**".....

Not long ago, I've posted a link to a program called Spool Capacity written by some European (German?) guy that will do exactly that plus a bit more.

Problem was that all the data to be entered must be in Metric which made me to use yet another conversion table plus length conversion from whatever yard to meter and vice versa.... PITA.

Soon after, someone from this board posted a URL to a site that does this in lb and yards..

I was happy with this site until I recently noticed that some conversion result don't quite seem to add up. So I ran the same conversion on this European program and confirmed that the results are quite different.

I think I know which one is way off but....

Least one of this program is deceiving and **I am wondering if anyone who has access to a good line meter can verify the calculation result by actually testing it?**

Here is a chart I got off of internet and added some unit conversions to ease the pain in using that European program.

# Spool capacity w/ diff. line diameters - conversion calc.

### #1

Posted September 27 2007 - 8:36 AM

### #2

Posted September 27 2007 - 11:28 AM

I have always used a ratio of line diameters. For example, if the stated spool capacity is 300yrds of 30lb mono and you want to use braid, adjust the capacity by the ratio of the two diameters. If the diameter 30lb mono is .17 and the braid is .05 you will get roughly 3 times a much braid on the spool.

*"I just do what the voices in my tackle box tell me to do."*

### #3

Posted September 27 2007 - 11:53 AM

I have always used a ratio of line diameters. For example, if the stated spool capacity is 300yrds of 30lb mono and you want to use braid, adjust the capacity by the ratio of the two diameters. If the diameter 30lb mono is .17 and the braid is .05 you will get roughly 3 times a much braid on the spool.

Now i see why your an engineer

### #4

Posted November 07 2009 - 11:54 PM

sheez..ive been lookin for that info for quite a while! thanks dude!Now i see why your an engineer

if i have a baitcaster that only holds up to twenty lb mono...how much

braid can i add on there and whats the highest test i can add?

### #5

Posted November 08 2009 - 7:21 AM

Its not quite as simple as a ratio of the two line diameters. In the same (square) space taken up by one thickness of 0.15 diameter line, you can fit nine thicknesses of 0.05 diameter line because the area taken up is inversely proportional to the * square* of the diameter.

Even though the line packs into the indentations between the line below it and packs tighter, the relationship holds. The relative amounts of line that can fit on the spool is inversely proportional to the area that each line occupies so,

*Line capacity of spool using line B*=

*Line capacity of spool using line*A[Area occupied by line B/Area occupied by line A]

-OR-

*Line capacity of spool using line B*=

*Line capacity of spool using line*A[(diameter of line A)(diameter of line A)]/[(diameter of line B)/(diameter of line B)]

This means that if a line is 1/2 as thick, the same spool can hold 4 times as much of the smaller line. If it is 2/3 as thick, the spool will hold 2-1/4 times as much line. If it is 3/4 as thick, the spool will hold a little over 1-3/4 times as much.

Even if you decide to calculate an estimate using this information, it would only be an educated guess because most braids do not stay anywhere as close to round as mono lines do. They flatten out and pack tighter making it much harder to estimate line capacities. The best way to get a good estimate is to find a line calculator that is based on actual measurements of amounts of braid and mono lines packed onto the same reels.