Sealcoat Calculator
Estimate the gallons of sealer a driveway or parking lot needs from its area, the number of coats, and the coverage rate.
Always check the product label for its coverage rate. Crack sealing and surface prep should come before sealcoating.
This calculator divides the pavement area by the sealer's coverage rate and multiplies by the number of coats. Coverage depends heavily on pavement condition: rough, porous, or older asphalt drinks more sealer than a smooth, recently paved surface.
Manufacturers publish coverage rates per gallon for their product — always check the label, since concentrates, ready-mix sealers, and sand-loaded mixes differ. Use this estimate to buy roughly the right quantity with a small buffer, not to replace product-specific instructions.
How this calculator works
Coverage rate: sealer is applied thin. A common planning figure is around 70 square feet per gallon per coat, but rough or thirsty pavement can drop well below that. Adjust the rate to match your product and surface.
Coats: most sealcoating jobs use two coats. Two thin coats wear better and cover more evenly than one heavy coat.
Buffer: the calculator adds an optional overage so you don't run short mid-job. Sealer left in the pail is easier to deal with than a half-finished driveway.
- Gallons per coat = Area (ft²) ÷ Coverage rate (ft²/gal)
- Total gallons = Gallons per coat × Number of coats
- With buffer = Total gallons × (1 + Buffer % ÷ 100)
Sealer needed by driveway size
Two coats at about 70 sq ft per gallon per coat, before buffer. Rough or never-sealed asphalt absorbs more — lower the coverage rate for those surfaces.
| Driveway size | Approx. area | Gallons (2 coats) |
|---|---|---|
| 1 car (10 × 20 ft) | 200 sq ft | ~5.7 gal |
| 2 car (20 × 20 ft) | 400 sq ft | ~11.4 gal |
| 3 car (30 × 20 ft) | 600 sq ft | ~17.1 gal |
| Large (1,000 sq ft) | 1,000 sq ft | ~28.6 gal |
Frequently asked questions
How many gallons of sealer do I need per square foot?
At about 70 square feet per gallon per coat, a single coat needs roughly 0.014 gallons per square foot; two coats need about double that. A 1,000 square foot driveway therefore needs roughly 28–30 gallons for two coats, before adding a buffer.
How many coats of sealcoat should I apply?
Two coats is standard for most driveways and lots. Two thin coats bond and wear better than one thick coat, which can crack or stay tacky. High-traffic commercial surfaces sometimes get additional coats in drive lanes.
Why does my pavement need more sealer than the calculator says?
Old, rough, and porous asphalt absorbs more sealer, lowering the effective coverage rate. If your surface is weathered or has never been sealed, lower the coverage rate (more area used per gallon becomes fewer square feet per gallon) to get a more realistic quantity.
Should I sealcoat myself or hire a contractor?
Small, sound residential driveways can be a reasonable DIY project. Large lots, badly cracked or failing pavement, and surfaces needing crack sealing first are usually better handled by a contractor who can prep the surface and apply commercial-grade sealer evenly. Crack repair should always come before sealcoating.
How much sealer do I need for a 1,000 sq ft driveway?
About 28–30 gallons for two coats at a coverage rate of roughly 70 square feet per gallon per coat, before adding a buffer. Older, rougher pavement can push that higher because it absorbs more sealer.
How long does sealcoat take to dry?
Most sealers are dry to the touch within a few hours but need longer before traffic — commonly 24 to 48 hours depending on temperature, humidity, and the product. Always follow the manufacturer's cure time on the label, and avoid sealing when rain is expected.
How often should a driveway be sealcoated?
A common interval is every 2 to 4 years, depending on climate, traffic, and pavement condition. Sealing too often wastes material and can lead to buildup; waiting too long lets oxidation and water damage the asphalt. Reseal when the surface looks gray and worn rather than on a rigid schedule.
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