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Fishing Hook Sizes Guide Explained to my 10-year-old boy​

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We were out for giant Groupers in the mediterranean sea. I wanted to check if they would chase a new Multi Jointed Swimbait I got on Amazon, and my son stuck to his junior spinning rod with some dead shrimps as bait.

While I didn’t get any action, my boy did, and after two small sea brims that were released un-harmed, he hooked a strong grouper that, sadly, when it was 3ft from where we stand, he managed to get away while snapping my son’s hook 🙁

Imagine the look he gave me when he rolled in the line to discover his #6 Gamakatsu Octopus Circle Hook cut in half.

So he rained on me a slew of queries about fish hook sizes, what size he should have utilized for this grouper, and I found myself rummaging through my brain to guide him through the expertise while attempting to keep it as basic (and interesting enough not to lose his 2022 children’s attention).

First thing first: What is a fishing hook size?

A fishing hook size is simply the measurement of the gap between a fishing hook’s point and shank.

The shank, point, barb, and eye are the four components of a hook. A fishing hook’s shank is the long, straight section. It extends from the gap (the cut-out region between the point and shank) to near where it meets with the eye at its end. The size of your bait can.

The point is the most critical component of a hook, as it allows your hook to pierce an animal’s mouth when you’re attempting to catch fish. It’s also what makes or determines whether it’ll be simple for an angler to pull their caught fish from the water. A decent hook point should be sharp, thin, and robust.

The barb is a small projection on the bottom of the shank that keeps your bait from being removed by any predator once it’s been hooked. The thicker its diameter, the better your catch will be protected during a fierce struggle with a fish or another predator.

A fishing hook’s eye is the end of the line or lure that connects to it, and it’s typically composed of stainless steel. The manner in which an angler ties their knots also affects how well a fishing hook holds on firmly throughout your entire outdoor excursion.

What are the most common hook sizes?

Fishing hooks sizes range from tiny #32 and up to giant 20/0.

In between the scale goes from #32 to #1 and then keeps growing from 1/0 to 20/0.

To get an idea of the actual size, a #6 hook gap is 9mm in width, while a 2/0 hook gap is 17mm. we have a full Hook Size Chart you can learn more about and find your preferred hook size.

The most common freshwater hook sizes are from #20 for flies to a big 10/0 for catfish, while for saltwater and boat fishing they get larger to handle sea monsters.

At this point, my son showed his brilliant mind (forgive me for this :), and asked me “What hook size should I use if there are different species and sizes?”

Of course, I was proud of him because his question shows a good grasp of the situation. As for the answer, my short version was: Pick the smallest hook size you can get away with (I got A menacing look to remind me of the grouper who got away…)

The longer answer is that you have another option – If you want to hook a big fish and decrease the chance of losing him to wick-hook (or line, or rod), go bigger and know that you’ll miss all small-medium fishes in your spot.

He accepted my longer explanation and asked:

So what hook should I use for the grouper that got away? (Or largemouth bass, or catfish, etc.)

Many newbie anglers ask this question in similar words; the most common is “How do you know what size fishing hook to use?

As for my son and his specific case, I said, “I’m guessing the grouper was a 10lb (4.5kg) grouper, so a size 2/0 should be sufficient. But a size 2/0 hook would not help you because your junior rod would have snapped under its weight”.

For all anglers asking this general question, generally speaking, you should use the smallest-sized hook that will still fit the bait. utilizing a hook too large for the appeal will often result in missed fish.

As you can probably understand, we’re entering a wider world of baits and the species they are fit to.

Here are a few examples:

  • A small hook (#6 – #2) is excellent for use with live bait, like minnows, that would work perfectly for walleye and trout.
  • For larger baits, like cut bait or chunks of fish, you’ll want to use a medium or large hook (2/0 – 5/0) that would work well with salmon and gar.
  • If you’re using artificial lures, experiment until you find the best size for the lure and fishing conditions. Hooks can be as small as a #16 hook for fishing tiny lures or as large as a #4 hook for fishing more extensive, heavier baits.


How to measure fishing hook size?

In the world of fishing, there is a wide range of fishing hooks to choose from. Some people would say it is easy to measure what size hook you need for different situations, but others might disagree.

To determine how to measure hook sizes in a few simple steps, keep reading!

In the fishing world, there are two main types of hooks: Standard and Treble. They both have different measurements to consider when choosing a size, so it’s important that you get this right before going fishing!

It might be helpful if you measure your hook against an object that is about the same length as your fishing line.

You might think that hook sizes are really easy to figure out, but they can be a little more complicated than you may expect.

In general, the bigger your fishing line is in diameter, the bigger the hook size should be so that it doesn’t slip off of your fishing line!

To determine what size hook you need, measure the fishing line’s diameter and then find a hook size that is close.

How to measure fishing hook size – More things to consider:

1) The size of the fish you will catch

2) The type of water you are fishing in

3) Your personal preference

4) What bait you are using.

5) How deep do you want to fish for your catch.

6) If it is saltwater or freshwater fish.

7) Hooks come in different sizes and shapes, be sure to pick one that has the right kind of curve for what type of fish you are trying to catch.

8) The hook’s weight should also be taken into consideration if there is more than one person fishing with hooks on the line together; this can help make sure everyone gets their fair share when they reel in their catches.

Fishing hook size chart actual size – PDF version to download

This is quite tricky because the actual size of hooks online is changing by the resolution your computer or phone has…

As for PDFs, you’ll have to print them and your printer settings can affect the outcome.

So I did my best and added the size in mm to each of the hooks.

Also, you’ll see that I create two charts, one for J fish hooks which would cover almost all hooks, and another one for treble hooks being double the gap naturally.

*** Please take under advice that different brands have hook size differentiation ***

fishing hook size chart actual size

Fishing Hook Size Chart In Mm

What size fishing hook should you use for the type of fish you are trying to catch?

This chart can help you determine the right size hook for your needs. It includes common hook sizes in millimeters so that you can easily find the right size for your fishing rod.

Whether you’re a beginner or an experienced angler, this chart will come in handy!


How to know what size of hook you need?

  • If you are fishing for smaller fish then fishing hook sizes can be very small, but if fishing in saltwater or freshwater lakes and rivers then the fishing hook size will need to increase.
  • Since fishing is an art form there isn’t really a “one size fits all” answer when trying to determine what fishing hook size you need.
  • There are fishing hook sizes that can fit into a child’s fishing kit and fishing hook sizes that can be used to catch large fish like sharks, so the range is quite wide in this case.
  • One of the best ways to determine what fishing hook size you will need for your next fishing trip is to look for a fishing hook size chart

Understanding How Fishing Hooks are Measured in Millimeter Form

Fishing hooks are usually measured in millimeters, but the displayed hook size is showing the hook size scale which for the un experience eye would say nothing about the actual size of the hook, that is why you should check our fishing Ho ok Size Chart in mm to make sure you buy what you need.

Choosing the Right Fishing Hook Size for Different Catch Rates & Rigging Techniques

There are different types of fishing hooks of different sizes and shapes. Each size has its own unique function and is used for specific fishing techniques.

The first thing to consider when choosing a fishing hook is the type of bait that will be used, as this determines the size of the hook that will be most appropriate for that bait. The second thing to consider is what you want to catch – big game fish, light tackle fish, or shrimp. This will determine which rig you use, which in turn will determine how heavy-duty your hook should be.

Fishing Hook Size Chart (In mm)


Length (mm)

Gap (mm)

Length (inches)

Gap (inches)


Hook sizes for bass

Striped BassJ-hook, Jighead, Circle hook, Worm hookFrom #1 circleTo 8/0 worm hook
Peacock BassBait Hook, Wide Gap Hook, J-hook, Jighead, Worm HookFrom #3 bait holderTo 4/0 worm hook
Smallmouth bassAberdeen hook, Worm hook, Octopus hook, Treble hook, Circle hook, Siwash hook, Kahle hookFrom #8 circleTo 1/0 siwash
Largemouth bassAberdeen hook, Worm hook, Octopus hook, Treble hook, Circle hook, Siwash hook, Kahle hookFrom #4 octopusTo 8/0 worm hook

Fishing hooks sizes for trout

Circle hook, Bait hook, J-hook, Jighead, Barbless hookFrom #20 circleTo #6 J-hook

Fishing hooks sizes for King Salmon

Circle hook, Octopus hook, Salmon egg hook, Siwash hookFrom #1 octopusTo 4/0 circle

Hook sizes for Walleye

Wide Gap Hook, Octopus Hook, Treble hooks, Circle hooks, Baitholder hookFrom #6 wide gapTo 4/0 slow death


What hook size is bigger 1 or 1.0?

Although they are close in size, 1.0 is the bigger one of the two. The 1 hook is called #1, which is in the smaller hooks range. Here is their actual size to get an understanding.

What size hook is bigger 8 or 10?

The short answer is that the 10 is the bigger one. However, you need to be clear about what you are asking. You should ask “What size hook is bigger 8/0 or 10/0”, and the answer would be 10/0, or, you can ask “What size hook is bigger #8 or #10, and in this case, the answer is #8.

What size hook is bigger 8 or 10?
The short answer is that the 10 is the bigger one. However, you need to be clear about what you are asking. You should ask “What size hook is bigger 8/0 or 10/0”, and the answer would be 10/0, or, you can ask “What size hook is bigger #8 or #10, and in this case, the answer is #8.

Which hook size is bigger 1 or 2?

Same here, are you asking about 1/0 0r #1. Cause 1/0 is smaller than 2/0, while #1 is larger than #2.

Which hook size is bigger 1 or 2?

How big is a #4 hook?

17 mm in length, 12 mm gap \ 0.63 inches in length, 0.43 inches gap

What is a 1 OT hook?

OT stands for Aught, which is the fishing hooks size system.

As for the 1 OT, AKA 1/0, it’s part of the bigger side of the hook’s size range, with a 34 mm length and 16 mm gap.

What is 2/0 hook actual size?

2/0 hook actual size length is 39mm or 1.53″, while it’s gap is 17mm or 0.67″

What is 3/0 hook actual size?

3/0 hook actual size length is 42mm or 1.65″, while it’s gap is 18mm or 0.70″

What size hooks for crappie?

Crappie’s mouth isn’t wide, so the idle hook size will range from #6 to #2 at most. Anything bigger can cause you to lose your catch.

What size hook is best for bass?

It depends on what kind of bass you are after…

For Largemouth bass you can use a small #6 Octopus hook, to a large 4/0 Aberdeen, and even a number 8/0 Worm hook.

For Smallmouth bass I would recommend a #8 circle hook and no larger than 2/0 Aberdeen.

What size hook is bigger 4 or 6?

A 6/0 is bigger than 4/0, while a #4 is bigger than #6

What size hook is bigger 4 or 6?

What size hooks are good for bluegill?

Bluegill has a tiny mouth so keep your hooks small – #6 to #10 Aberdeen will be great

What size hooks for bream fishing?

Bream’s hook size is similar to the Smallmouth bass, so you can test hook from #4 and up to 2/0.

What size is a 4/0 hook?

A size 4/0 is a large hook (unlike the size #4 hook). A 4/0 hook actual size is 47mm in length and 19mm wide (gap) so it’ll fit for fish species with a relatively big mouth.

What size is a size 1 hook?

A size 1 is a bit of a trick question since there is no such hook size. Hooks size comes with a # before the size number or a /0 after.

So the right questions can be either “What size is #1 hook” or “What size is 1/0 hook”. The answer for the 1st one is about a 10mm gap while the second will be around a 12mm gap.

Which hook size is bigger 1 or 2?

Like the question above, we need to differentiate between #1 – #2 hooks to 1/0 – 2/0. For the 1st pair, the #1 hook is bigger than #2, while as for the 2nd pair it’s the opposite, 2/0 is bigger than 1/0.

How big is a size 8 fishing hook?

If you’re asking this you probably referring to the #8 hook which has about a 6mm gap.

What do fish hook sizes mean?

Because of the different types of hooks and the parts they are made of (ex. shank), the best way to refer to hook size is by measuring its gap (the circle part of the hook or the part that connects the shank and the point.

What size of hook is the biggest?

There is no definitive answer to this question as the biggest fishing hook size will depend on what you are trying to catch and where you are fishing. However, some of the largest fishing hooks can be up to 20/0 or even larger. These hooks are typically used for catching very large fish such as sharks.

7/0 hook

This is a big hook and is used in saltwater fishing. It can be used to catch smaller fish like tuna, mackerel, and bonito as well as larger fish like marlin and swordfish.

I hope that this article has helped you to understand the different sizes of hooks and how they are used. As with anything, practice makes perfect so get out there and start using the right size hook for the type of fish you are targeting. Remember to have fun while you’re fishing and be safe!