Driveway Sealing Calculator
| Driveway | Area | Pails (1 coat) | DIY cost | Pro at $0.20/sq ft |
|---|---|---|---|---|
| Single car 10x20 | 200 sq ft | 1 | ~$40 | $40 |
| Two car 18x20 | 360 sq ft | 1 | ~$50 | $72 |
| 18x40 | 720 sq ft | 2 | ~$75 | $144 |
| 24x50 | 1,200 sq ft | 3 | ~$100 | $240 |
Sealcoat math starts with coverage, not price: a five-gallon pail of asphalt sealer spreads across roughly 400 square feet on the first coat and up to twice that on the thin second coat, which means a typical two-car driveway is a two-pail job before any arithmetic humility.
Bottom line: length times width gives the area, area divided by 400 gives the pails, and DIY lands near 30 to 80 dollars against a professional quote of 15 to 25 cents a square foot - the pro buys you crack-filling, edges and no Sunday spent pushing a squeegee.
The honest part: sealing is maintenance, not repair - it darkens and protects sound asphalt but does nothing for alligator cracking or potholes, which want fill first. And fresh asphalt waits a year: sealing too early traps the oils a new driveway needs to cure.
How to use
- Measure length times width of the paved area - ignore the apron if the municipality owns it - and read the pail count with one coat as the budget line.
- Compare the DIY total (pails plus a squeegee plus a crack-fill tube) against the per-square-foot pro quote before committing a weekend.
- Check the weather window: two dry days above 50 degrees, no rain in the forecast, and morning application so the surface cures before evening dew.
Frequently asked questions
How much does a 5 gallon pail of driveway sealer cover?
About 400 square feet on a first coat over dry, sound asphalt - up to 800 on a maintenance second coat where the first filled the pores. Rough driveways drink more: add a pail for heavily pocked surfaces, and never thin the sealer to stretch it, which halves the protection and voids the point.
How often should you seal a driveway?
Every two to three years for most climates - annually in freeze-thaw heavy regions with plow damage, and never on new asphalt inside its first year. The tell is color: gray, faded asphalt is asking; if water no longer beads on the surface, the seal is gone and the oxidation clock is running.
Is driveway sealing worth it or a scam?
The math splits by who holds the squeegee: DIY at 30 to 80 dollars a season is cheap prevention against a 4,000-plus-dollar repour, while door-hanger crews charging 15 to 25 cents a square foot with undiluted product are legitimate. The scam version is the drive-up crew offering a today-only price with a diluted, spray-and-pray coat - real contractors measure, quote and schedule.
When is it too cold to seal a driveway?
Below 50 degrees the emulsion will not cure - it stays tacky, tracks into the garage and washes off in the first rain. The sealing season is late spring through early fall, and the fall deadline matters: seal too late and the first freeze kills the coat before it has cured, which is why the calculator's weather window matters as much as the pail count.