Ice Fishing Sonar Cone Coverage Calculator
Calculate fish-finder sonar cone diameter at any depth.
Enter cone angle and water depth to see coverage diameter and area at the bottom for ice fishing.
Cone Diameter at Depth
Sonar Cone Coverage
A fish-finder transducer emits a cone-shaped beam of sound. The wider the cone angle, the more area is scanned — but the lower the resolution per square foot.
The cone diameter formula: Diameter = 2 × Depth × tan(Cone Angle / 2)
Common ice-fishing transducer cone angles:
| Angle | Use Case |
|---|---|
| 8° | Tight cone, max resolution, struggling to find fish off-axis |
| 12° | Standard medium-cone — Vexilar FL series, MarCum |
| 16° | Wider — covers more, less detail |
| 20° | Wide cone — search/scout, less ID detail |
| Dual (12° + 20°) | Modern split-screen units — best of both |
Practical examples (12° cone — most common):
| Depth | Cone Diameter | Coverage Area |
|---|---|---|
| 10 ft | 2.1 ft | ~3.5 sq ft |
| 20 ft | 4.2 ft | ~14 sq ft |
| 30 ft | 6.3 ft | ~31 sq ft |
| 40 ft | 8.4 ft | ~55 sq ft |
| 60 ft | 12.6 ft | ~125 sq ft |
| 100 ft | 21.0 ft | ~346 sq ft |
For ice fishing specifically:
- Cone diameter at the bottom = how far away a fish can be detected
- A wider cone shows more “blips” but is harder to use for placing your jig precisely on a fish
- For deep lake trout (60-100 ft), wide cones miss less; for shallow panfish (10-20 ft), tighter cones give better jig-presentation feedback
Side-by-side jigging: If you and a buddy drill holes 6 ft apart in 30 ft of water with 12° cones, your beams overlap heavily. Drill at least 8-10 ft apart to avoid mutual detection.
Best ice-fishing electronics tips:
- 8-12° cone for finesse panfishing
- 16-20° for searching new structure
- Always confirm cone angle in your unit’s spec sheet — manufacturers vary