Aught

Also called hook size, 2/0, 1/0

What does aught mean in hook sizes?

How hook sizes above size 1 are spoken. 2/0 is 'two aught', and bigger aught numbers mean bigger hooks.

Panfish: Size 8
General bait fishing: Size 2
Soft plastic worms: 3/0 EWG
Full sequence: 20 → 1 → 1/0 → 5/0; Small to large

How does the hook size scale work?

Hook sizing runs backwards and then flips. Plain numbers get smaller as the number gets bigger: a size 6 hook is bigger than a size 10, which is bigger than a size 14. Then the scale passes through size 1 and switches to the aught system, written with a slash and a zero, where the numbers get bigger as the hooks get bigger. 1/0, 2/0, 3/0 and up.

So the full sequence from tiny to huge runs 20, 14, 10, 6, 2, 1, 1/0, 2/0, 5/0.

Why is hook sizing so confusing?

There is no logic to recover here; it is a historical artifact of wire gauge numbering and you simply learn it. Nothing about the scale is derivable, which is why even experienced anglers check a chart when they move to an unfamiliar hook style.

Sizes are also not standardised between manufacturers or between hook patterns, so a 3/0 worm hook and a 3/0 circle hook are different objects.

What size hook do you actually need?

This is the single most common reason beginners buy hooks that are far too big for the fish they are catching. A bluegill will not fit a 2/0 in its mouth, and a hook that never gets taken looks exactly like water with no fish in it.

Match the hook to the bait and the mouth, not to the fish you hope to catch.

In practice

Three sizes cover a first year: size 8 for panfish, size 2 for general bait fishing, and 3/0 EWG for soft plastics.

What this means when you’re choosing

The hook pattern alongside the size. A 3/0 extra wide gap and a 3/0 Aberdeen have almost nothing in common.
A small assortment rather than a big pack of one size, at least until you know what you fish.
The gap rather than the number when comparing two brands, since it is the measurement the number is standing in for.

The common mistake

Buying big hooks for big fish

A larger hook looks like it holds a larger fish, and mostly it just stops the bite happening. Hook size is set by the size of the bait and the mouth taking it, not by the fish's weight, and a heavy bass is landed on a size 2 every day. Undersized hooks catch fish; oversized ones catch nothing at all.

Common questions

Why do fishing hook sizes go backwards?

Plain numbered sizes shrink as the number rises, so a size 14 is smaller than a size 6. Above size 1 the scale switches to the aught system, written 1/0, 2/0 and up, where bigger numbers mean bigger hooks.

What size hook should a beginner buy?

Size 8 for panfish and bluegill, size 2 for general live bait fishing, and 3/0 extra wide gap for soft plastic worms. Those three cover almost everything in the first year.

Where this comes up

The guides that use aught and show it on real gear.

Last reviewed August 22, 2026. Aught is one of 222 terms in the fishing glossary.