Asphalt sealer calculator
For parking lots, commercial driveways, and roads. Coal-tar emulsion at 250 sqft/gal, asphalt emulsion at 200, oil-based at 150. Two coats are standard; a 10,000 sq ft parking lot needs ~80 gallons (one tote or 16 pails).
Coal-tar vs. asphalt emulsion
Coal-tar lasts longer (~3 years vs. 2 years for asphalt emulsion) and resists oil and gas spills better. Several states (Washington DC, Maryland) have restricted or banned coal-tar sealers due to PAH runoff into waterways. Asphalt emulsion is the eco-friendlier compromise.
5-gallon pails vs. totes
Up to 50 gallons: pails make sense. Above that, a 275-gallon tote is much cheaper per gallon and easier to handle if you have squeegee or spray equipment. Pro contractors get sealer delivered in 5,000-gallon tankers for very large jobs.