| Size | Gap (mm) | Size | Gap (mm) | |------|----------|------|----------| | #32 | 1.5 mm | 1/0 | 11 mm | | #24 | 2.0 mm | 2/0 | 12.5 mm | | #20 | 2.5 mm | 3/0 | 14 mm | | #16 | 3.5 mm | 4/0 | 16 mm | | #14 | 4.0 mm | 5/0 | 18 mm | | #12 | 4.5 mm | 6/0 | 20 mm | | #10 | 5.0 mm | 7/0 | 22 mm | | #8 | 6.0 mm | 8/0 | 24 mm | | #6 | 7.0 mm | 9/0 | 26 mm | | #4 | 8.0 mm | 10/0 | 28 mm | | #2 | 9.0 mm | 12/0 | 32 mm | | #1 | 10.0 mm | 14/0 | 36 mm |
If you use a 5/0 hook with a 2-inch minnow, the bait will not swim naturally, and the fish will feel metal before tasting food. The hook gap should never exceed the width of the baitfish’s body. fishing hook size chart in mm
For larger hooks, as the number before the slash increases, the hook gets larger (e.g., a 6/0 is much larger than a 1/0). Factors That Affect mm Dimensions Hook Size Chart - The Complete Saltwater Fishing Hook Guide | Size | Gap (mm) | Size |
In fly fishing and finesse lure fishing, "matching the hatch" refers to selecting a bait that mimics the natural food source of the fish. If you know the insects or baitfish in your local lake are roughly 15mm long, looking for a hook with a specific millimeter gap allows for precise pairing. You aren't guessing; you are measuring. Factors That Affect mm Dimensions Hook Size Chart
| Traditional Size | Approx. Gap (mm) | Best For | |----------------|----------------|----------| | #12 | 4–5 mm | Tiny midges, trout flies | | #8 | 6–7 mm | Panfish, small baitfish | | #6 | 8–9 mm | Bluegill, small trout | | #4 | 10–11 mm | Crappie, perch | | #2 | 12–13 mm | Bass, walleye (small plastic worms) | | #1 | 14–15 mm | Bass, catfish (live bait) | | 1/0 | 16–18 mm | Largemouth bass, redfish | | 2/0 | 19–21 mm | Pike, small musky, snapper | | 4/0 | 24–27 mm | Musky, large catfish, tuna | | 6/0 | 30–33 mm | Big pike, shark (small) | | 8/0 | 38–42 mm | Shark, grouper, big game | | 12/0 | 55–60 mm | Giant trevally, large shark |
The traditional numbering system is inconsistent:
This scale is used for large predatory fish. Unlike the standard scale, the numbers get larger as the hook gets bigger.