Pick the geometry, measure the space, and the tool multiplies by the label's dust rate to give grams to load — then how much of a 1 lb (453.6 g) jar that is. The circle-area step for conduit (the one most people skip) is done for you.

Open void (box):   volume_ft³ = L × W × D
                   grams      = volume_ft³ × void_rate      (1 g/ft³ default)

Conduit (cylinder, the label's own equation):
                   radius_ft  = (diameter_in / 12) / 2
                   volume_ft³ = π × radius_ft² × length
                   grams      = volume_ft³ × void_rate

Surface (broadcast / thin layer) — two label forms, you pick one:
   g/sq yd:        grams = (area_ft² / 9) × rate_g_sqyd     (1 sq yd = 9 ft²)
   lb/1,000 ft²:   grams = (area_ft² / 1000) × rate_lb × 453.6

All modes:
   with_buffer = grams × (1 + buffer)        (buffer default 10%)
   jar_fraction = with_buffer / jar_g        (jar default 453.6 g = 1 lb)
   jars_to_buy  = ceil(jar_fraction)

Why two surface numbers diverge: the label's 2–3 g per square yard works out to ≈0.28 g/ft², while 0.5 lb per 1,000 square feet is ≈0.23 g/ft². They are two different statements on the same label — we show only the basis you pick and never average them, because no label authorizes a blended rate.

About the buffer: the 10% is a procurement cushion so you don't run short on a job — not a license to over-dust. The label says apply lightly and uniformly; over-application repels pests and raises exposure.

The 1 g/ft³ void rate and 2–3 g/sq yd surface band are stated in identical language across the DeltaDust (Envu/Bayer) and D-Fense Dust (Control Solutions) EPA labels — both 0.05% deltamethrin dusts. They are editable defaults, not authoritative figures: desiccant and boric-acid dusts differ, so override the rate for the product you actually have.

Insecticide Dust Quantity Calculator

Sources