Pick your lawn area (rectangle, circle, triangle, or a total you already know), choose your grass species and whether this is a new lawn or an overseed, and we multiply your area by that species' coverage rate. The New lawn / Overseed toggle picks the rate column — overseeding runs about half of a new establishment rate.

area (sq ft):
  rectangle = length × width
  circle    = π × radius²            (π = 3.14159)
  triangle  = (base × height) / 2
  total     = your number, converted to sq ft

rate = species rate (new or overseed column)  — or your custom rate
seed (lbs) = (area / 1,000) × rate
seed (kg)  = seed (lbs) × 0.45359237

bags     = ceil(seed / bag weight)
leftover = bags × bag weight − seed
cost     = seed × price per lb

Coverage rates are typical per-species values from Inch Calculator and Omnicalculator. They are a starting point, not a guarantee — the rate on your seed bag label governs, and overseed ≈ half of new-lawn is a rule of thumb. Use the Custom rate option to enter the exact figure from your bag.

Formula: seed (lbs) = (area ÷ 1,000) × rate; bags = ceil(seed ÷ bag)

See Sources below