Aught
Also called hook size, 2/0, 1/0
How hook sizes above size 1 are spoken. 2/0 is 'two aught', and bigger aught numbers mean bigger hooks.
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. There is no logic to recover here; it is a historical artifact of wire gauge numbering and you simply learn it.
This is the single most common reason beginners buy hooks that are far too big for the fish they are catching.
Three sizes cover a first year: size 8 for panfish, size 2 for general bait fishing, and 3/0 EWG for soft plastics.
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.
Related terms
Where this comes up
The guides that use aught and show it on real gear.
Aught is one of 206 terms in the glossary.
Browse the full fishing glossary