Driveway Sealer Calculator

A 20 × 30 ft asphalt driveway is 600 sq ft. Sealing it with two coats of asphalt emulsion sealer takes about 3⅓ pails, so buy 4 pails of 4.75 gal, when the surface is rough or has never been sealed; a smooth, previously sealed drive needs 2½, so 3 pails. The makers' data sheets rate a pail at 300 to 500 sq ft per coat depending on the surface, and the second coat soaks up less than the first.

How driveway sealer is calculated

pails = driveway sq ft ÷ sq ft per pail per coat × coat factor, rounded up

The coat factor is where sealers differ:

• Asphalt emulsion (Latex-ite, Black Jack Drive-Maxx): coverage is per coat, and Latex-ite says the second coat takes about ⅓ less product than the first. Two coats = 1 + ⅔ = 1.67 × one coat.
• Coal tar: SealMaster rates its ready-to-use Coal Tar E-Z Stir at 70 to 82 sq ft per gallon per coat. Each coat counts in full.
• Acrylic: Latex-ite rates its 3.4 gal Acrylic Grade at about 400 sq ft with two thin coats (300 on rough asphalt), so the rating already includes both coats.

Coverage per pail by sealer and surface

Latex-ite's data sheets give ranges of 300 to 400 sq ft per pail on rough and 400 to 500 on smooth surfaces; the calculator uses the low end of each so you do not run out halfway down the drive. Black Jack's Drive-Maxx sheets are lower still, 300 on rough and 350 on smooth, so if you buy that brand expect one more pail on a big drive.

Worked example: 600 sq ft, rough, two coats

Latex-ite's own FAQ example is the same size, 10 × 60 ft on rough asphalt, and suggests 2 pails for the first coat and 1 for the second. Our 4 pails leaves room for a thirsty surface; an unopened pail can usually be returned.

One coat or two?

Two thin coats cure better than one thick one: Latex-ite explains that water-based sealers cure by evaporation, and a thick coat holds water, stays soft and tracks into the garage. Black Jack's Drive-Maxx line requires two coats. Pull the squeegee with steady pressure and let the first coat dry overnight.

Crack filler by crack length

Fill cracks before you seal. Add up the length of every crack and pick its width:

• Pourable filler, 1 gal jug: Black Jack rates its 3.6 qt jug at about 75 ft of ¼ in cracks; SealMaster rates its acrylic filler at 75 to 150 ft per gallon. The calculator uses 75 ft and scales up for wider cracks, since fillers go in no more than ¼ in thick with backer rod below. 40 ft of ¼ in cracks is one jug.
• Caulk tube, 10.1 oz: up to 32 ft of ¼ in bead (Latex-ite).
• Heat-applied rope: Latex-ite Crack-Stix comes in 125 ft rolls for ½ in cracks and 225 ft for smaller ones.

Cracks wider than about ¾ in need patching rather than filling; the repair mode of the asphalt calculator counts cold patch bags.

What sealing costs

Fixr (January 2025) lists material at $0.08 to $0.10 per sq ft for coal tar, $0.15 to $0.20 for asphalt emulsion and $0.25 to $0.35 for acrylic, so the 600 sq ft example costs about $90 to $120 in emulsion sealer. A professional sealcoat runs $0.88 to $2.10 per sq ft, most around $1.05: about $530 to $1,260, typically $630.

When to seal

Wait about six months after new asphalt goes down, seal when the ground is at least 45°F with no rain forecast for three days, and reseal every 5 to 10 years, sooner with cheaper sealers (Fixr). Coal tar is banned in some areas because of what runs off it into groundwater; check before you buy it.

Next questions

• Pricing a new driveway instead? The driveway calculator compares asphalt, concrete and gravel.
• Sealing gaps where the drive meets the garage slab or the house: the caulk calculator.
• Striping or painting other surfaces: the paint calculator.

All driveway tools are on the driveways and paving hub.