How Much Fishing Line is Left on my Spool?

how much fishing line is left on the spool

Good morning brothers.

Have you ever wondered how much fishing line you have left on your spool?

I’m not asking if you’ve wondered how much is sitting on the spool of your reel – I’m asking if you are looking for a way to tell how much fishing line you have left after spooling up?

Ever tossed out a spool with fishing line still on it instead of attempting to use every last yard, because you thought there wouldn’t be enough for more than one spool? It sucks, but it’s understandable. We don’t want to put ourselves in a situation where a big ‘ol fish could start ripping drag and spool us completely… but hey, good news:

This is how you get the MAXIMUM use out of a spool of fishing line.

Creek Fishing Carp Inline Spinner
Glad I was using braid this morning and didn’t get spooled… this was an awesome fight in the kayak!

Using the following method saves money and guesswork, but first, grab a new spool to work with:

How to Spool Multiple Fishing Reels with Less Line

I love to use braid. And fluorocarbon. And Braid with fluorocarbon leaders. Or braid with monofilament backing. These fishing lines are expensive, but you can save some money if you buy them in bulk. However, I don’t respool enough to justify 3,500 yards of braid or fluoro… so like most mere mortals, I stick with the 150 or 300 yard spools.

While most fishing reels show some sort of line capacity guide right on the side of the spool (or the reel itself) it’s typically shown in a diameter that I am NOT planning to use.


The Lew’s shown above will hold 120 yards of fishing line with the diameter of 6lb monofilament.

The Pflueger shown above will hold 200 yards of fishing line with the diameter of 2lb monofilament.

So the volume of line your spool can hold is dependent on the size (diameter), not the strength rating (pound test).

If you are doing a straight spool – let’s say we’re going to fill the Lew’s 100% with 10 pound test InvizX – then the conversion from 6lb test mono to 10lb test fluoro is rather straightforward. A common average diameter for 6lb test mono is 0.009″ (that’s inches), and an average for 10lb fluorocarbon is 0.010″ (again, inches – make sure you get the exact diameters of the lines you’re using, in the same unit of measurement).

By plugging in the diameter of both lines (0.009″ & 0.010″) and the starting capacity of the reel (120 yards) we can see that it is possible to put 97 yards of fluorocarbon on our spool.

line reel calculator fishing line mono to fluorocarbon

This means that if our fishing line spool for the InvizX fluorocarbon contains 200 yards to start – we can completely spool up two of the reels in our example with 97 yards each, and even have a few yards to spare. This allows me to spool up without using some sort of line counter or wasting any expensive fishing line.

We’re eliminated the guesswork.

Here’s a link to the line calculation tool I used for this example.

Here’s another example. Let’s say we want to put 40lb braid on our small Pflueger spinning reel that holds 200 yards of 2lb test mono (for some unknown reason) – that conversion looks like this:

fishing line calculator berkley to braid spool

Not a great idea… but even if we decided to do this, we would know that we only used 30 yards off of our 300 yard spool of braid. We have 270 yards remaining for a baitcaster.

What about Advanced Line Calculations?

You can also figure out other fishing line combinations using this tool for advanced line calculations.

Let’s say we want to add some monofilament backing to a Lew’s Mach II Baitcaster.

This reel has a spool that will accomodate 110 yards of 12lb diameter line. (Again, these sizes are usually still listed in monofilament, which is why on packages of braided line you usually see a diameter for “mono equivalent“.)

I want to add some leftover mono to my new baitcaster as backing so that the braid has something to “bite into” (even though this isn’t required on spools with holes in them – just run the line through before you tie your knot to prevent slippage). This will prevent it from slipping on the spool (I know, I know, this is mainly an issue on spinning reels, not baitcasters – just work with me here! This is an example!), and I just so happen to have 20 yards of 6lb monofilament left over from my first example…

Step 1: Add the spool capacity (110 yards of 10 pound mono which is 0.013″)

Step 2: Add your backing material (20 yards of 6 pound mono which is 0.005″)

Step 3: Plug in your mainline (65lb Sufix 832 braid which is 0.016″ )

Step 4: Read the results… with this combination, my spool will hold 71 yards of 65lb braid, and the overall length of my line plus my backing is 91 yards. That is total length of the line on the spool, even though this spool is rated to hold 110 yards.

We’re using thick braid, and additional backing, but we still know exactly how much we can fit onto the reel, and how much we have left on the 300 yard spool of fishing line!

advanced fishing line calculation tool

Bookmark this page.

The next time you’re respooling in the garage, griping about the price of braid & fluorocarbon, grab these calculators so you can maximize your fishing line usage!

Tight (Accurately Measured) Lines & Godspeed, Patriots.

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