Driveway sealer calculator
Asphalt sealcoat at ~250 sqft/gal needs reapplication every 2–3 years; concrete sealer at ~400 sqft/gal goes 5–7 years. Standard 16'×50' driveway = 800 sq ft = 4 gallons (one 5-gallon pail) for asphalt or 2 gallons for concrete.
Asphalt sealcoat: every 2–3 years
Asphalt oxidizes — sun and water break down the binders that hold the aggregate together. Sealcoat replenishes a black surface coat that protects the underlying asphalt. Skip sealcoating and the driveway cracks and crumbles in 7–10 years instead of 20+.
Concrete sealer is different
Concrete sealers penetrate the surface (siloxane, silane, acrylic) rather than forming a thick film. Coverage is much higher (~400 sqft/gal) and reapplication is every 5–7 years. Salt resistance and stain protection are the main benefits.
Application: weather window
Both asphalt and concrete sealers need 24+ hours of dry weather and surface temps above 50°F. Mid-summer is ideal — early spring or fall risks rain interruption.