Cockroach Gel Bait Calculator

Two interchangeable input modes feed one shared spots → grams → tubes back-end. Pick the mode that matches how you measured — the tool never averages the two.

Mode A (linear feet):
  spots          = ceil( (linear_ft / 10) × spots_per_10ft )
  gel_used       = spots × grams_per_spot

Mode B (floor area):
  gel_used       = (area_sqft / 9) × grams_per_9sqft_effective
  implied_spots  = round( gel_used / grams_per_spot )   // cross-check only

Both modes:
  gel_with_buffer = gel_used × (1 + waste_pct)
  tubes_needed    = ceil( gel_with_buffer / tube_size )

Severity rate map (Mode A, spots per 10 ft): light = 2, moderate = 2, heavy = 4. Cockroach Facts gives one band for light/moderate (1–3) and one for heavy (3–5), so light and moderate share the same midpoint.

Area gram rate (Mode B, grams per 9 sq ft): light = 1.5, moderate = 2.25, heavy = 3.0, then × 1.0 for small species or × 1.5 for large. The single cited anchor is Better Termite's 3 g per 9 sq ft for a heavy job; the lighter-severity and species scalars are derived defaults, surfaced as editable overrides — not cited manufacturer specs.

Constants (all editable under Advanced): 0.5 g per spot (pea-sized; PCT band ¼–½ g), 30 g per tube (Advion / label-typical low end of 30–35 g), 10% waste buffer. Grams-per-spot above 0.5 g still computes but flags the bait-aversion caution rather than blocking. The tube count rounds up on the un-rounded grams-with-buffer, so a buffer landing exactly on a tube boundary (e.g. 30.0 g) is one tube, not two.

Sources: Cockroach Facts (0.5 g/spot, spots-per-10-ft bands, bait-aversion); PCT — Pest Control Technology (¼–½ g spot weight, species-banded placements per sq yd, 3–4 in from harborage); Better Termite (3 g per 9 sq ft, 30–35 g tube size).

Grams of gel is a cost input, not a price. Turning the placements, the prep visit and the follow-ups into a number for a unit or a whole building is the job of the cockroach treatment pricing calculator. Baiting ants runs on the same logic but a different placement pattern and bait class, which the ant bait placement and rate calculator covers. Voids and wall cavities are treated with dust rather than gel, and the insecticide dust quantity calculator sizes that side of the same visit. Gel alone rarely holds a heavy account either: the sanitation, harborage and exclusion work that sits around it is the integrated pest management half of the program.