Choosing hooks: Wire gauge formula
Two hooks of the same size can differ in wire. Two rules tell you where a hook sits.
Rule 1, the X convention. nX strong (heavy) = the standard wire of a hook n sizes larger. nX fine = the standard wire of a hook n sizes smaller. A 2X strong 3/0 has roughly the wire of a standard 5/0.
Rule 2, measure it. Gauge index = measured wire diameter ÷ standard diameter for that size.
| Size | #1 | 1/0 | 2/0 | 3/0 | 4/0 | 5/0 |
|---|---|---|---|---|---|---|
| Standard wire (mm) | 0.90 | 0.98* | 1.05* | 1.13 | 1.24* | 1.35 |
Standard = Decoy Worm5 offset, measured; * = between measured sizes.
| Gauge index | Class |
|---|---|
| under 0.85 | Fine (finesse) |
| 0.85–1.05 | Standard |
| 1.05–1.15 | Heavy (strong) |
| over 1.15 | Extra heavy (heavy cover, punching) |
Worked examples (measured wire):
| Hook | Size | Wire (mm) | Index | Class |
|---|---|---|---|---|
| Nogales Light, Ryugi Hobbit, Decoy Worm19 | #1 | 0.65–0.70 | 0.72–0.78 | Fine |
| Decoy Worm9 Upper Cut | 3/0 | 1.12 | 0.99 | Standard |
| Decoy Worm4 Strong Wire | 3/0 | 1.21 | 1.07 | Heavy |
| Decoy Worm25 Kg Wide | 3/0 | 1.24 | 1.10 | Heavy |
| A "2X strong" 3/0 (rule 1) | 3/0 | ≈1.35 | ≈1.19 | Extra heavy |
At the same size the spread is small (3/0 offsets measure 1.12–1.24 mm); the big gaps are at finesse sizes (#1 runs 0.65–0.90 mm). US makers' "3X / 4X / 5X" is often a strength rating, not a diameter: Owner's Zo-Wire is thinner and stronger. Class ranges and the index thresholds are this site's reading of the measured data.
← Straight or offset · Matching wire to line and rod →
Choosing hooks
Straight or offset, fine or heavy wire (with a formula), the wire for your line and rod, hook size for each soft bait, every way to hook a drop shot, and hook eyes: which way they face and at what angle.