Can Fishing Line Be Too Heavy? Tips For Choosing the Right Size

Many fishermen believe that if they put a heavy line on their reels, they will catch bigger fish. Although this can be true, there are some things that should be considered when lining your reel. So can fishing line be too heavy?

Yes, fishing line can be too heavy. Adding a bigger line than is recommended on the reel will reduce the line capacity on the spool. Additionally, line that is too heavy for the rod will make it difficult to cast small lures or baits. Line size should be within the range listed on the rod and reel.

fishing rod bending

Now that we have established that line size can be too heavy, how do you select the correct line for your rod and reel? Below we will discuss how to properly pair your line to help you avoid equipment failures and lost fish. 

How much weight can a fishing line hold?

Before we dive into how to pair line with your rod and reel combo, let’s review the strength of fishing line and some mechanics of fighting a fish.

Fishing line is measured in pound test. The use of pounds indicates the breaking strength of the line when under tension. It does not account for things such as abrasion or wearing through the line. Fishing line can range from 2lb test all the way up to 200lb test and will be made of monofilament or braided fibers.

Does heavier line catch bigger fish?

The biggest misconception when it comes to selecting line is that you need a heavy line to land big fish. This is not necessarily true and in fact, fishing line is far stronger than you might think.

The average angler does not put even 10lbs of pressure on the line when fighting a fish. If you were to tie your line to a scale and fight it like a fish, you would be surprised how little pressure you are actually putting on the fish.

Since the rod is designed to bend and absorb the tension, the amount of pressure you are applying is significantly reduced. Therefore the maximum amount of pressure that can be applied is determined by the rod angle. Pointing the rod directly at the fish with no bend in the rod will apply the most pressure as the weight is now directly on the reel fighting the amount of drag. For more information on this concept, check out Why do fishing rods bend?

Since the amount of pressure we apply to the fish is far less than expected, big fish can be landed on relatively small lines. In fact, large fish such as tarpon are commonly landed on 20lb test.

seaguar leader material

Line strength becomes more important when applying leader material to the end of your fishing line.

What is fishing leader material?

Leader material is a clear section of line that helps hide the visibility of your main fishing line and is attached to the end of your fishing line. The hook is then tied to the end of the leader material.

I personally would recommend using Seagar leader material.

Thicker leader pound test is added when fishing for toothy species or when fishing around structure and snags. When fishing for spooky species, such as bonefish, leader size can be reduced to make the line less visible. For a list of common leader sizes, be sure to check out What size saltwater leader?

What happens if you put too heavy line a reel?

Even though we do not need a very heavy line to catch big fish, why not go heavier just to be safe? 

The biggest drawback of adding too heavy a line to a reel is the capacity of line that can be held on the reel. Heavier lines are thicker in diameter and therefore take up more space. Reel manufacturers have tested line capacity and will add recommendations of different line sizes directly to the reel.

There is nothing worse than having a big fish on the line and watching him spool you because you had too little of line on the reel. I would much rather have more line on the reel and loosen the drag than have to over-tighten the drag in fear of the fish taking all my line. Remember, you can always add a heavier piece of leader to the line. 

Additionally, over time your fishing line will become shorter. This is from losing line to snags on the bottom or clipping and re-adding leader material. Using a heavier line will force you to re-spool your reel more frequently than having using a smaller diameter of line.

How to select line size for your reel?

The easiest way to select a line for your reel is to review the line capacity markings imprinted on the reel. These markings will not only give you the line size range but will also tell you the capacity of each size. 

For example, if we review the picture below of a Penn 5500 series reel, you will see the suggested line size is between 10lb and 30lb test. Next to each line size is the capacity in yards. You will notice that the 10lb monofilament capacity is 360 yards of line.

fishing line too heavy close up

Reel manufactures will give these recommendations in both mono and braid. Looking at the picture above you will notice both markings. Since the braid is a thinner diameter, the capacity will be greater.

Braid vs Mono: Which is better?

The sport of fishing is always evolving and therefore the equipment must keep up. Monofilament used to be the only option of fishing line, but over time the introduction of braided fishing lines has changed the landscape.

Braided line is a series of twisted threads that create a very thin rope. The strength of braided line is far stronger than monofilament and therefore allows it to be equally as strong at thinner diameters. Unlike monofilament, braid does not retain memory. If you have ever left a reel with a monofilament line sitting for a long time between use, you may notice that when you cast, the line is coiled. This is because the line has recorded the memory of the spool. This makes casting mono lines very difficult, whereas casting braided line is far smoother and tends to cast further. 

There are some drawbacks to using braided line however. Braid will not stretch like mono will. This can make it difficult to absorb hard strikes when fishing heavy gear or bottom fishing on a reef. Also because the braid is made of thread, it is not as abrasion resistant to rubbing against structure. Lastly is the cost. Braided lines are far more expensive than monofilament lines and it can become costly when spooling multiple reels. 

Overall, if you are an inshore fisherman or someone who enjoys casting lures, I would highly recommend using braided fishing line. For offshore fishermen who like to fish deep wrecks, the benefits of mono line will be better when no casting is involved. 

braided line close up

If you are looking for a braided line, I would highly recommend Power Pro products. For a complete list of lines that I recommend, head over to my Recommended Products page

What does line weight mean on a rod?

Have you ever looked at the marking on a fishing rod and became confused? When I first started fishing, these numbers were all Greek to me, but over time I have learned that they are a significant part of setting up your fishing outfit correctly.

The line weight listed on a rod is the suggested range of line size to be used on the rod. The numbers are denoted in pound test and correspond to the action and size of the rod. For example, a Medium Light rod with fast action will have a suggested line weight of 4lb up to 10lb. 

Similar to the markings on a reel, the manufacturer has done testing to find the ideal line size to pair with their rods. The line size of a rod is designed with casting in mind. Too heavy of a line can make it difficult to cast lures or even worse can cause the rod to break while fighting a fish. 

The size of the suggested line corresponds to the size of the rod. Rod sizes can range from Light all the way up to extra heavy. As you can guess, a light rod will use smaller lines whereas a heavy rod is designed for heavier lines. The heavier the rod, the stiffer it becomes.

rod marking fishing line too heavy

What does the action of a fishing rod mean?

In addition to sizes, rods have different actions as well.

The action indicates how flexible the tip of the rod is. A fast rod tends to be a bit stiffer than a slow rod and can be cast with a faster whipping motion. The size of the rod and action will also determine the weight of the lure or sinker that can be cast.

Rods will have markings, listed in ounces, that depict the weight casting capabilities of the rod. If we look at the above picture, you will see this rod is designed to cast 1/8oz weights up to 1/2oz weights.

Every manufacturer will list these markings slightly differently on their rods. The general rule of thumb is that line size will be denoted by two numbers separated with a dash and the suggested lure size will be denoted in fractions or the use of the “oz” symbol. The size of the rod will be given the following range:

MLMedium Light
MHMedium Heavy
XHExtra Heavy


Using a line that’s too heavy while fishing is not necessary to land large fish. The amount of pressure we put on the fish while fighting it is far less than we think. As a fishing rod bends, the amount of pressure on the fish is reduced, making the heavy line less effective.

 Having too heavy of line on your reel will limit its capacity. Also, it could result in the fish taking all of your line. Using a braided line is a great way to add additional line capacity and make casting to longer distances easier. 

 When the line is too heavy for your rod, casting will become difficult and could actually lead to rod breakage. Your rod will be marked with the suggested line size and lure weight capabilities.

 If you are unsure what line size to use for your rod and reel, refer to the rod and reel for recommended sizes.