Sealcoat calculator: how much driveway sealer do I need?
14 gallons
3 pails of 5 gal · 480 sq ft × 2 coats at 70 to 82 sq ft per gallon per coat · 11.7 to 13.7 gallons across that range · for a 20 × 24 ft driveway
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14 gallons
3 pails of 5 gal · 480 sq ft × 2 coats at 70 to 82 sq ft per gallon per coat · 11.7 to 13.7 gallons across that range
Source: SealMaster, MasterSeal Ultra Pavement Sealer technical data sheet SMT-153 (revised April 6, 2023), read October 20, 2026. Data sheet (PDF)
A 20 by 24 ft driveway takes 14 gallons of sealcoat for the two coats SealMaster calls for: its MasterSeal Ultra data sheet gives 70 to 82 square feet per gallon per coat, so 960 square feet of coats is 13.7 gallons.
A worked example
A 46 by 9.5 ft single-car driveway with two coats needs 13 gallons. The driveway is 437 square feet, 874 with both coats. At 70 square feet per gallon that is 12.49 gallons, so 13, in 3 pails of 5 gallons; at the 82 end it would be 10.66.
How many square feet does a gallon of sealcoat cover?
70 to 82 square feet per gallon per coat for SealMaster MasterSeal Ultra, a ready-to-use sealer, by its data sheet: 7.75 to 9.1 square yards. Since it goes on in two coats, a gallon finishes 35 to 41 square feet of driveway.
How many coats of sealcoat does a driveway need?
At least two, by SealMaster, with a third on high-traffic areas such as entrances, exits and drive lanes. Each coat dries before the next, the last one gets 24 hours before cars go on it, and it is not applied when the temperature will drop below 50°F within 24 hours or rain is forecast within 12.
What else it is called
Sealcoat is also called driveway sealer, asphalt sealer or blacktop sealer, and the job sealcoating. Searched as a sealcoat calculator, asphalt sealcoat calculator or driveway sealer calculator. Sealer is counted in gallons; the pail size is a field because stores sell different ones.
Gallons by driveway size
| Driveway | Square feet | Gallons at 70 sq ft | Gallons at 82 sq ft | Gallons to buy | 5 gal pails |
|---|---|---|---|---|---|
| 10 × 20 ft | 200 | 5.71 | 4.88 | 6 | 2 |
| 12 × 24 ft | 288 | 8.23 | 7.02 | 9 | 2 |
| 18 × 36 ft | 648 | 18.51 | 15.80 | 19 | 4 |
| 20 × 20 ft | 400 | 11.43 | 9.76 | 12 | 3 |
| 20 × 24 ft | 480 | 13.71 | 11.71 | 14 | 3 |
| 24 × 24 ft | 576 | 16.46 | 14.05 | 17 | 4 |
| 20 × 40 ft | 800 | 22.86 | 19.51 | 23 | 5 |
Two coats of SealMaster MasterSeal Ultra at 70 to 82 sq ft per gallon per coat, by its data sheet; gallons to buy at 70. A third coat on entrances and drive lanes adds half again.
Where the numbers come from
- Coverage and coats: SealMaster's technical data sheet for MasterSeal Ultra Pavement Sealer (SMT-153, revised April 6, 2023), a ready-to-apply asphalt emulsion sealer that meets ASTM D8099: «One gallon of MasterSeal Ultra will cover approximately 70 - 82 square feet per gallon per coat», with a minimum of two coats and a third on high-traffic areas such as entrances, exits and drive lanes. Read October 20, 2026. Data sheet (PDF)
- The rest is arithmetic: square feet × coats ÷ 70, the low end of the range so the last coat does not run short, rounded up to the gallon; pails rounded up.
The 70 to 82 square feet are for a ready-to-use sealer. A concentrate that is mixed with water and sand on site covers a different area per gallon of concentrate: put the figure on its sheet in the optional field.
By Javier Miralles · Last updated . How this site is made.
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