Fishing Hook Size Chart and Guide: Actual Sizes, by Species

On a fishing hook size chart, a smaller number means a bigger hook from #32 up to #1. Then the scale flips to “aughts”, written 1/0, 2/0 and so on, and the numbers rise as the hooks grow, up to the 20/0 of a shark rig. Every beginner asks whether a #2 or a #4 is bigger, and the answer, the #2, is the one that feels wrong. The number describes the hook’s gap, not its length: on Mustad’s Octopus a #4 gapes 0.41 in, a 4/0 nearly twice that. This guide gives each size in inches and mm, then the size for each fish and each bait, because the bait you put on the hook decides the size before the fish does.

A #2 hook is bigger than a #4, and a 2/0 is bigger than a 1/0. The scale runs down to 1, then flips and runs up again, and nobody who learned it the hard way forgets.

What you need

• The hooks hub for the hook types and the parts of a hook; this page is about size only.
• A ruler. The gap of the hook, point to shank, is what the size describes, and the number to check against the chart.

How do fishing hook sizes work?

Size 1 is the hinge: below it the numbers count down as the hooks grow, above it the aughts count up. The table gives the approximate gap of each range on a J hook, and what it is for.

Below the hinge, #10 is a panfish hook, #6 a trout-bait hook and #2 a walleye hook. Above it, 1/0 is said “one aught”, and each step adds a little more gap. Only even numbers are common below #1, so a tackle wall skips the odd sizes until it reaches #1 and the aughts.

Read the number as gap, not length. The size says how far the point sits from the shank, which sets how much bait the hook holds and how big a mouth it fits. A long-shank Aberdeen and a short-shank octopus of the same size are meant to share a gap and nothing else. Even the gap is approximate: in Mustad’s tables below, the #6 cricket hook gapes 0.28 in (7.1 mm) against the #6 octopus’s 0.35 in (8.8 mm). The sizes are not a standard either: each maker sets its own. The ranges above are rounded from Mustad’s tables from #10 up and estimated below that, where its tables stop. For any other hook they are approximate, and the maker’s own table is the one to trust.

Free PDF · Hook size chart What size is that hook? Lay it on the chart.

Print the free chart, lay any hook on it and read its size: 14 hooks from 9/0 to #8 at actual size, a gap ladder from #32 to 12/0, and the size for 17 fish and 16 baits on the back.

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Fishing hook size chart in inches and mm

Mustad publishes gap, length and wire diameter for every size it makes, so the scale can be put in numbers, at actual size. This is its classic Octopus hook, pattern 92553, the walleye and salmon bait hook in every bait shop. The US catalog starts at #6; the UK catalog adds the #8, its smallest size.

Mustad 92553 Octopus, measured by the maker: #8 to 9/0.

So how big is a size 4 hook? On this pattern, 0.41 in (10.5 mm) across the gap and 0.71 in (18 mm) long. How big is a 4/0? It gapes 0.79 in (20 mm) and is 1.34 in (34 mm) long. And a 7/0? It gapes 1.02 in (26 mm) and is 1.81 in (46 mm) long. The free True-Size Hook Chart draws all 14 at actual size: print it at 100% and lay a hook on it to read its size.

Three things stand out. Each aught step adds about 2 mm of gap, so a 2/0 and a 4/0 differ by 4 mm, just over 1/8 in on a ruler. That is the difference between a hook that disappears in a 4 in worm and one that holds a 7 in worm with the point clear. From #6 to 9/0 the gap grows three and a half times and the wire three times. That is why a big hook needs a hard hookset on heavy line, and a small one sets itself on 4 lb mono. And length grows faster than gap, because the maker lengthens the shank to carry a bigger bait.

Aberdeen hook size chart

Mustad’s classic Aberdeen, pattern 3261, is a long-shank, all-round bait hook, and its table starts smaller than the Octopus: #12 to 1/0. Mustad lists gap and length for it, not the wire.

Mustad 3261 Aberdeen, measured by the maker: #12 to 1/0.

Size for size, the Aberdeen gapes less than the Octopus: at #4, 8.7 mm against 10.5 mm. At 1/0, 12.2 mm against 14.5 mm. It also comes in the odd sizes, #7, #5 and #3, that most packets skip. The cricket hook 3261D is the same Aberdeen on a 4X long shank, with the same gap at every size Mustad lists for it (#10 to #4).

Why is a 2/0 not always a 2/0?

Because the number is a label the maker gives a pattern, not a measurement. Two patterns from the same catalog can wear the same number on very different hooks, and Mustad’s own tables make the point better than any rule of thumb.

The #6 cricket hook is 2.4 times as long as the #6 octopus, with a smaller gap: the long shank holds a cricket and gives a bluegill angler something to grip. The 2/0 circle hook gapes less than the #4 octopus, because a circle hook’s point curls back toward the shank and the usable gap is the throat. That is why the circle hook sizes for catfish and stripers look so big next to the J-hook sizes here. It is also why a circle hook one or two sizes larger than the J hook it replaces is normal.

Hook size chart by species

What size hook for each fish? From the small #8–#12 bluegill hook to the tuna’s 10/0 circle, with the line test to match each fish. Where a species page exists, its bait-specific size wins over this starting range. The line column is a starting pound test; the line hub explains when to go heavier.

Tackle Village’s tiers cover panfish, trout, walleye, carp, channel catfish and pike; the largemouth bass and catfish pages cover bass, blues and flatheads; the Tackle Room’s braid classes cover salt. A bluegill angler after the biggest fish in the school drops to 2 lb, and a catfish angler fishing a 10/0 for trophy blues goes well past 20.

One rule runs through the table. For bait fishing, match the hook to the bait rather than the fish, on a circle hook that sets itself in the corner of the mouth when the fish runs. The best catfish bait page sizes each bait, and the circle hook page has the rules on where circle hooks are required.

Bass hook size chart

Largemouth take a 3/0 to 5/0 extra-wide-gap worm hook. Smallmouth go a size or two smaller, 2/0 to 3/0. On a drop shot, a #1 or 1/0. Academy’s chart gives the same two ranges, both on worm hooks: the smaller for smallmouth on live bait or small soft plastics, the larger for largemouth on live bait or large ones. Within the range the plastic decides, as the worm hook size chart below shows. Most worm hooks have wide gaps, Bass Pro notes, so the point can clear a bulky plastic on the hookset.

Bluegill and crappie hook size chart

Bluegill and other sunfish take a #8 to #12 and crappie and perch a #6 to #10, both on a light-wire Aberdeen. Academy’s chart gives bluegill the same Aberdeen in the same sizes. On the Aberdeen chart, a #10 gapes 0.17 in (4.4 mm). A #6 gapes 0.28 in (7.1 mm). The light wire earns its place in crappie timber: Bass Pro notes that a snagged Aberdeen can sometimes be bent and pulled free with a bit of pressure.

Salmon and shark hook sizes

Academy’s chart gives salmon a 2/0 to 4/0 Siwash hook for trolling and spinning. Salmon eggs drifted in a spawn sack are a bait question, in the bait section below. For sharks, The Tackle Room gives 8/0 to 12/0 circle hooks inshore. Large sharks get 16/0 to 20/0, the top of the scale. At 16/0 a circle hook gapes about 1.5 in (39 mm).

Trout and catfish hook size charts

The trout row and the three catfish rows are starting points. The trout hook size chart breaks trout down by bait, lure and fly, and the catfish hook size chart sizes channels, blues and flatheads by bait.

What size hook for each bait?

The bait sets the size before the fish does, because the hook has to hold the bait with the point clear.

The catfish rows follow FishUSA’s quick picks (channels 1/0–4/0, blues 5/0–7/0 on chunks and 8/0–10/0 on heads), widened to 8/0 on chunks where Academy’s chart and Catfish Pro put it. The 6/0 note is Catfish Pro’s line that a 6/0 handles channels of all sizes to the mid-teens of pounds. The punch-bait treble sits inside Tackle Village’s #6 to #1 range for catfish trebles. The catfish hub has the rigs these hooks go on.

A spawn sack for steelhead is sized by the sack, not the fish. Pautzke ties them from dime to quarter size, four king salmon eggs to twenty, hooked through the netting opposite the knot. And Bass Pro’s live-bait primer gives the test for an offering that is too big: a fish that keeps nibbling is usually telling you the presentation is too large. Shrink the bait, and the hook with it.

Worm hook size chart

For soft plastics the length of the bait picks the hook, by Mystery Tackle Box’s sizes for bass.

A fluke on a 3/0 wide-gap, short-shank hook dives nose-first into cover instead of falling slowly. A tube on light line drops to a 1/0. Pitching a 4–5 in tube on heavy line, go up to a 4/0. The rigs hub has the rigs that put these hooks to work.

Hook size guide: how to choose, step by step

1. Start from the bait, not the fish. The hook has to hold the bait with the point clear: a nightcrawler on a #4, a 6 in worm on a 4/0, a bluegill through the back on an 8/0.
2. Check the mouth. A bluegill cannot take a 1/0; a flathead swallows a 10/0 whole. The species table gives the range.
3. Pick the type, which changes the gap at a given size: extra-wide-gap for plastics, circle for bait, Aberdeen for small mouths and snaggy timber.
4. Match the wire to the line. Light wire on 4–8 lb mono, standard wire on 10–20 lb, 2X or 3X strong on braid and for fish that run into cover.
5. Go one size smaller in clear water and for finicky fish, one size larger in cover and for big baits.
6. Read the packet. The maker’s chart, drawn to scale, is the only exact one; hold a hook against it if in doubt.

What do 2X strong and 2X long mean?

They say how far the hook departs from the maker’s standard hook of that size. A packet often carries one beside the size: 2X strong, 1X fine, 2X long or 2X short. The X system comes from fly hooks. A 2X long has a shank about two sizes longer, so a #10 2X long carries the shank of a #8 on the gap of a #10. A 2X strong (some makers say “heavy”) is made of heavier wire than the standard hook of that size, and a 1X fine of lighter. The steps are relative to each maker’s own standard, not to each other’s.

Mustad’s tables show the labels in metal. The Demon circle is sold as 3X strong and 2X short, and its 2/0 is drawn from 1.42 mm wire, the wire of the 4/0 octopus, on a shorter hook. The cricket hook is 4X long, and its #6 is as long as the 5/0 octopus. Which gauge to buy follows the line. Light wire penetrates on 4–8 lb mono and bends straight out of a snag, the point of an Aberdeen in crappie timber. Heavy wire holds a bass on 65 lb braid and needs a hard hookset. Finish and point are on the types of hooks page.

What about treble hook sizes?

Trebles use the same numbers with the same reversal, in a shorter range: The Tackle Room’s treble chart runs from #8 to 5/0. Lures often ship a size smaller than the guides suggest. Rapala’s 4 in Husky Jerk wears #6 trebles, and Heddon’s 5 in Super Spook, a topwater, ships with #4. The Tackle Room’s rule for swapping: one size up or down rarely hurts the action, two can throw off the balance, and the replacement should match the weight of the original so the lure still runs true. On a suspending jerkbait that weight is the difference between suspending and sinking. The full treble hook size chart, with the gap of each size and the lures that wear it, is on the treble hook page, and the crankbait hub explains the weight.

How do you measure a hook you have?

When the packet is gone, or when a rule depends on it, measure the gap. Lay the hook on a ruler and read from the tip of the point straight across to the inside of the shank, with the ruler at right angles to the shank. That is the number the chart describes and the one regulations use.

Idaho’s salmon rules make it “unlawful to use any hook larger than 5/8 inch measured from the point of the hook to the shank”. That 5/8 in (16 mm) is not a hook size. On Mustad’s octopus table a 1/0 passes at 0.57 in and a 2/0 fails at 0.63 in, while another maker’s 2/0 might pass. Where the law names a gap, measure the hook, not the label.

Mistakes to avoid

• Reading the scale the wrong way. A #6 is smaller than a #4; a 6/0 is bigger than a 4/0. The slash is the hinge.
• Choosing by the fish’s weight. A 20 lb catfish bites a 2/0 with a small bait on it; a 2 lb bass takes a 5/0 with a big worm. Bait first.
• Too small for the mouth. A #10 in a 4 in minnow hooks nothing but the minnow, and a small hook deep in a big bait gut-hooks the fish that swallows it, the deep hooking Take Me Fishing warns about.
• Too big for the bait. A 4/0 on a finesse worm kills the action; drop to a 1/0 or 2/0, or a #1 drop-shot hook. If the point cannot clear the plastic on the set, the hook is too big or the plastic too small.
• Judging size by length. The #6 cricket hook above is longer than a 2/0 octopus and still a bluegill hook. Length is the shank; size is the gap.
• Assuming brands and patterns match. Check the gap when you change makers, and expect a circle hook to run one or two sizes bigger than the J hook it replaces.

What else decides the hook?

Size is one of three hook decisions. The type is the second, and the hooks hub covers the ten styles. The third is the law: whether the water requires a circle hook for the fish you are after, or a barbless hook.

Free PDF · 2 pages

Lay any hook on this page and read its size

The True-Size Hook Chart. Print it at actual size and lay a hook on the outlines: the one its bend fills is its size. One sheet, front and back, for the tackle box.

• 14 hooks from 9/0 to #8 at true size, each with its gap and length in inches and millimeters
• Smaller than #8 or bigger than 9/0? Measure the gap and read the size off the ladder, #32 to 12/0
• The size for 17 fish and 16 baits, from bluegill (#8 to #12) to tuna (7/0 to 10/0)
• A 2/0 circle that gapes less than a #4: why a 2/0 is not always a 2/0, and the aught rule in two sentences

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Every outline drawn from Mustad's published dimensions; every size from the 25 sources on the page, Maryland DNR and Idaho Fish and Game among them.

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