Gallons of driveway sealer by surface condition and coat count — because a porous driveway drinks far more than a smooth one.
Sealcoating Calculator
Inputs
Two coats is standard. One is a touch-up, not a seal.
Results
Sealer needed
22.86 gal
gallons = ft² ÷ 70 × 2 coats
Calculated with BuildCalculators.com
Sealcoating is a coverage calculation, not a volume one. Sealer is spread thin, so the only things that matter are surface area, how porous the surface is, and how many coats you are putting down.
A worn, porous driveway drinks noticeably more sealer than a smooth one — which is why a single national coverage figure produces short orders on exactly the driveways that need sealing most.
gal = ft² ÷ coverage × coats80 ft² per gallon per coat70 ft² per gallon per coat60 ft² per gallon per coatpails = gallons ÷ 5Sealer fills the texture of the asphalt before it builds a film. A smooth, recently sealed surface has little texture to fill and covers at around 80 ft² per gallon. An older, oxidised, open surface can drop to 60 or below, because the first coat is largely disappearing into the pores.
The first coat penetrates and seals; the second builds the wearing film that actually resists water and UV. One coat on a porous driveway is close to pointless — most of it is absorbed rather than forming a surface. Two is the standard specification.
It slows oxidation and stops water reaching the base through the surface. It is not a structural treatment and it does not fill cracks — a crack under a coat of sealer is still a crack, and water still gets in. Crack filling is a separate job that comes first.
New asphalt needs 6–12 months before its first seal. The oils in fresh mix have to volatilise; seal too early and the coating will not bond, trapping them underneath and leaving a surface that peels off in sheets.
A typical residential driveway a few years old, two coats.
22.86 gallons — 5 × 5 gal pails
At around $35 a pail that is roughly $175 in material, against $120–$240 for a professional job on the same driveway. DIY sealcoating saves less than people expect.
Older surface, never sealed, visibly open texture.
26.67 gallons — 6 pails
A full pail more than the average-condition case. Ordering on the smooth figure would leave you short mid-job, and a partial seal is a wasted afternoon.
Commercial lot in average condition.
142.86 gallons
Above roughly 100 gallons, buy in 55 gallon drums rather than pails — it is meaningfully cheaper per gallon and far less handling.
Per gallon per coat.
| Condition | Coverage | Gal per 1,000 ft², 2 coats |
|---|---|---|
| Smooth, recently sealed | 80 ft² | 25.0 |
| Average residential | 70 ft² | 28.6 |
| Rough, oxidised, porous | 60 ft² | 33.3 |
| Very porous or unsealed | 50 ft² | 40.0 |
| Type | Cost per gal | Lasts | Notes |
|---|---|---|---|
| Asphalt emulsion | $0.15–$0.25/ft² | 2–3 yr | Most widely legal, low odour |
| Coal tar | $0.12–$0.20/ft² | 3–5 yr | Banned in many jurisdictions |
| Acrylic | $0.25–$0.45/ft² | 5–7 yr | Most durable, colour options |
| Fast-dry emulsion | $0.20–$0.30/ft² | 2–3 yr | Reopens in hours |
| Age of asphalt | Action |
|---|---|
| 0–6 months | Do nothing — let it cure |
| 6–12 months | First sealcoat |
| Every 3–5 years | Reseal |
| Any time cracks appear | Crack fill first, then seal |
| Alligator cracking present | Stop — sealing will not help, the base has failed |
Sealcoating is cheap relative to what it protects, which is what makes it worthwhile — but the DIY saving is smaller than most people assume once equipment and time are counted.
$0.15–$0.30 per square foot for two coats, so an 800 ft² driveway is roughly $120–$240. That includes cleaning, edging, oil spot primer and the labour of doing it properly.
$30–$45 per 5 gallon pail. The same driveway needs about 5 pails, roughly $175 — plus a squeegee or brush, crack filler and a day. The saving over a professional job is often under $100.
Pressure cleaning, oil spot primer, proper edge cutting and a consistent film thickness. A DIY coat that is too thin lasts a year rather than three, which erases the saving entirely.
Sealing an 800 ft² driveway costs $120–$240 every three to five years. Resurfacing the same driveway costs $1,600–$4,000. If sealing extends the surface by even a few years it pays for itself several times over — provided the base is sound.
Sealer is a coating, not a filler. It will not bridge a crack, and water continues to reach the base underneath. Crack fill first, let it set, then seal — in that order, always.
Fresh asphalt needs 6–12 months to cure. Seal it early and the coating cannot bond to the uncured oils, so it peels off in sheets within a season.
On a porous surface the first coat is largely absorbed. Without a second there is no wearing film, and the job needs redoing far sooner than the sealer would otherwise have lasted.
Ordering at 80 ft² per gallon for a rough driveway leaves you around 20% short. The driveways most in need of sealing are exactly the ones that drink the most.
Sealer on alligator cracking is cosmetic. The base has already gone, and a coating changes nothing structural — that money belongs in an overlay or a replacement instead.
Most sealers need 50°F and rising, no rain for 24 hours, and preferably shade. Applied in direct summer heat they skin over before curing underneath; applied cold they never cure at all.
Divide the area by the coverage rate and multiply by coats. A 40 × 20 ft driveway in average condition needs 800 ÷ 70 × 2 = 22.86 gallons, or five 5 gallon pails.
70 square feet per coat on an average surface. A smooth, recently sealed driveway reaches 80; a rough, oxidised one drops to 60 or lower because the first coat soaks into the pores.
Two. The first penetrates and seals, the second builds the wearing film. One coat on a porous driveway is largely absorbed and does not form a protective surface.
Six to twelve months. Fresh asphalt has to cure and release its oils first — seal it early and the coating will not bond, leaving a surface that peels off in sheets.
Every three to five years. More often than that wastes money and can build up a coating that cracks; much less often and oxidation gets ahead of you.
Marginally. Material for an 800 ft² driveway is about $175 against $120–$240 for a professional job that includes cleaning, oil spot primer and a consistent film thickness. The saving is often under $100 for a day of work.
Always. Sealer is a coating, not a filler — it will not bridge a crack and water keeps reaching the base underneath. Crack fill, let it set, then seal.
No. Alligator cracking means the base has failed, and a surface coating changes nothing structural. That money belongs in an overlay or a replacement.
Embed the Sealcoating Calculator anywhere — it is free, stays in sync with this page, and sizes itself to fit. The only condition is the credit line in the snippet, which links your readers to the full version with the formulas and worked examples.
This calculator uses published constants from named industry sources, each asserted in an automated test that runs on every build. The formula is printed with the result above, and any correction we make is logged on the changelog.
It is a planning estimate. It does not replace an engineer, a site visit or a written quote — confirm quantities with your supplier before ordering.