How deep does each color of lead core go?

A common rule of thumb is about 5 feet of depth per 10-yard color at a typical 2 mile-per-hour trolling speed, before any leader. So five colors run roughly 25 feet down. Slower speeds let it sink deeper; faster speeds lift it shallower.

What is a color of lead core line?

Lead core line is dyed in repeating 10-yard segments of different colors so you can count how much line is out at a glance. Each color you let out adds a predictable amount of depth, which is why anglers talk about fishing a lure at a number of colors rather than feet.

How does trolling speed change depth?

Faster trolling creates more drag on the line and lure, lifting them toward the surface, while slower trolling lets everything sink deeper. This calculator scales the base depth by your speed relative to a 2 mile-per-hour reference, so a 3 mph troll runs noticeably shallower.

Why does line diameter matter for braid and mono?

Thinner line cuts through the water with less drag and dives deeper for the same amount of line out, while thick line planes upward. The diameter factor in the braid and mono model rewards thin braid with extra depth, matching how dipsy and flat-line setups behave in practice.

Should I account for the leader and lure?

Yes. These estimates are for the line itself; a long mono leader floats and reduces depth, while a heavy diving crankbait adds depth on its own. Treat the result as a baseline and fine-tune with a line counter and any strikes you get at known depths.

Trolling Depth Calculator

Getting your lure into the strike zone is the whole game in trolling. This calculator estimates lure depth two ways: the classic lead-core colors rule and a line-out, diameter, and speed model for braid or monofilament.

How it works

For lead core, each 10-yard color adds a fixed depth, scaled by speed:

leadCoreDepth (ft) = colors × 5 × speedFactor

For braid or mono, depth grows with line out, increases for thinner line, and is reduced by speed:

baseDepth   = lineOutFt × diveRate(diameter)
speedFactor = 2.0 / trollingSpeedMph   (capped to a sensible range)
depth (ft)  = baseDepth × speedFactor

The 2.0 mph reference is the speed at which the rule-of-thumb numbers are calibrated. Faster than that and the lure planes upward; slower and it sinks deeper. Thin braid dives more per foot of line than thick mono.

Example and tips

Five colors of lead core at 2 mph run about 5 × 5 = 25 feet; speed up to 3 mph and the speed factor (2/3 ≈ 0.67) drops that to roughly 17 feet. For braid, 100 feet of thin 0.011-inch line at 2 mph might run near 18 feet, but only 12 feet at 3 mph. Add a long mono leader and you will fish shallower than these numbers; a heavy diving plug adds depth. Use a line counter reel to repeat depths that produce fish.