Ordering sealcoat takes 3 numbers: the net area in square feet, the label coverage in square feet per gallon per coat, and the coat count. Divide the area by the coverage, multiply by the coats, and round the exact total up once to the container size you can buy.
Start from the net area in the measure for asphalt sealcoat guide. That number already excludes islands and pads that stay unsealed. This article turns that area into gallons and containers. The sealcoat product guide decides which product family fits the pavement.
How much sealcoat do you need?
Use one formula for the whole order. Keep the area, coverage, coats, and container size on separate lines so each number can be checked.
Gallons per coat = net area in square feet ÷ label coverage in square feet per gallon per coat
Exact order gallons = gallons per coat × coat count
Containers = exact order gallons ÷ container gallons, rounded up
| Stage | Calculation or source | Record purpose |
|---|---|---|
| Net area | Measured sealed area in square feet | Defines the surface the order covers |
| Label coverage | Square feet per gallon per coat from the exact product label | Sets the gallons per coat |
| Coat count | Planned coats, usually 2 | Sets the multiplier on per-coat gallons |
| Exact total | Gallons per coat × coat count | Preserves the quantity before commercial rounding |
| Purchase quantity | Exact total rounded up once to the container size | Matches what the supplier can sell |
Which coverage figure does your label give you?
Coverage figures differ by product form, and the basis matters as much as the number. A concentrate figure counts only the sealer in the container. A mixed figure counts sealer plus added water. A two-coat figure counts both coats together. Read the basis line before dividing.
| Product form | Label basis | Stated coverage | Use in the formula |
|---|---|---|---|
| Coal tar concentrate | Concentrate gallons, per coat | 100 to 120 square feet per gallon | Divide area by this figure, then multiply by coats |
| Polymer-modified coal tar concentrate | Concentrate gallons, per coat | 85 to 95 square feet per gallon | Divide area by this figure, then multiply by coats |
| Coal tar ready-mix | Ready-mix gallons, per coat | 80 to 95 square feet per gallon | Divide area by this figure, then multiply by coats |
| Retail coal tar pavement sealer | Gallons for two coats combined | 50 to 60 square feet per gallon for two coats | Divide area by this figure for the full 2-coat job, with no extra coat multiplier |
SealMaster states the mixed application rate for its coal tar concentrate separately: 0.11 to 0.13 gallon per square yard per coat, equal to 70 to 82 square feet per gallon of mixed material. Mixed gallons include added water, so they run higher than concentrate gallons for the same area. Order concentrate gallons when you buy concentrate, and order ready-mix gallons when you buy ready-mix. Do not convert a mixed rate into a concentrate order without the mix design on the label.
Coverage varies with pavement age and porosity. A worn, porous surface takes more product per square foot than a smooth, dense surface. When the label gives a range, use the low end of the range for worn or porous pavement and the high end for smooth pavement in good condition. Record which end you used, so the order can be checked later.
Worked example: driveway in 5-gallon pails
A driveway measures 1,200 square feet net. The chosen coal tar concentrate label states 100 square feet per gallon per coat. The plan calls for 2 coats.
- Gallons per coat: 1,200 ÷ 100 = 12 gallons.
- Exact total: 12 × 2 = 24 gallons.
- Pails: 24 ÷ 5 = 4.8, rounded up to 5 pails.
- Purchase quantity: 5 × 5 = 25 gallons, with 1 gallon spare.
Result: order 5 pails of 5 gallons, or 25 gallons total, for a 1,200 square foot driveway at 2 coats under the stated 100 square feet per gallon label figure.
Worked example: lot in a drum plus a pail
A small lot measures 2,400 square feet net. The chosen ready-mix label states 80 square feet per gallon per coat. The plan calls for 2 coats.
- Gallons per coat: 2,400 ÷ 80 = 30 gallons.
- Exact total: 30 × 2 = 60 gallons.
- Containers: one 55-gallon drum plus one 5-gallon pail = 60 gallons.
Result: order one 55-gallon drum and one 5-gallon pail, or 60 gallons total, for a 2,400 square foot lot at 2 coats under the stated 80 square feet per gallon label figure. SealMaster lists 5-gallon pails and 55-gallon drums among its container sizes, but the sizes actually sold for your product come from its label and your supplier.
How do you round the order?
Round once, at the end, after coats are multiplied. Rounding per coat adds a rounding step that the supplier does not need, and it can add a whole container to the order. Keep the exact total beside the rounded purchase quantity so the spare amount stays visible.
Do not add a hidden percentage on top of a label range. The range already carries the surface variation. If a real extra quantity is needed, such as a separately measured high-traffic strip that takes a third coat, put it on its own line with its own area and coverage. SealMaster recommends a third coat on high-traffic areas such as entrances, exits, and drive lanes. That strip is a separate calculation, not a percentage added to the whole order.
| Choice | Rule | Why it matters |
|---|---|---|
| Round once | Round the exact total up to the container size, one time | Avoids a second rounding step that inflates the order |
| Use the range end | Low end for worn or porous pavement, high end for smooth pavement | Carries surface variation inside the label figure |
| Separate third coat | Calculate a high-traffic strip as its own area and coat | Keeps the main order checkable and the extra quantity visible |
| Named allowance only | Add a quantity only with a stated area, reason, and approval | Prevents the same uncertainty from being added twice |
What does dilution change?
Dilution changes the mixed volume, not the sealer gallons you order. Water added at mixing spreads the same sealer over the same area at the label rate. A concentrate order stays a concentrate order, and a ready-mix order stays a ready-mix order.
NEYRA states that its ready-to-use products need no dilution for most work, and that dilution of a ready-to-use product stays at or below 5% when equipment requires it. Follow the exact product label for dilution, sand, and additive. Sand and additive are separate order lines. They add texture and body to the mix, but they are not sealcoat gallons, and they do not replace a missing gallon of sealer.
What else belongs on the order?
Put the product name, product form, label coverage, coat count, net area, exact total, and container breakdown on the order record. Add crack filler as a separate line, since cracks are filled before sealing and crack filler is not counted in the sealcoat coverage. Confirm the container sizes, minimum order, and pickup or delivery terms with the supplier before the sealing date.
Check local legality before ordering a coal tar product. The product guide explains that some states and cities restrict or ban coal tar sealants, and that the local rule decides the product family. A correct gallon count for a banned product is still the wrong order.
Conditions that change timing, not quantity
SealMaster requires a minimum surface and ambient temperature of 50 degrees Fahrenheit during application and for 24 hours after, and a 4-week cure for new asphalt under ideal weather before coal tar application. These conditions decide when the work can happen. They do not change the gallon count. Do not order extra product to cover a cold or wet day. Reschedule the work instead.
Ordering mistakes
- Ordering by bucket count from a past job with a different area or product.
- Dividing by a mixed coverage figure when buying concentrate, or the reverse.
- Multiplying a two-coat coverage figure by 2 coats again.
- Rounding up per coat instead of once on the exact total.
- Adding a percentage allowance on top of a label range that already covers surface variation.
- Counting dilution water, sand, or additive as sealcoat gallons.
- Counting unsealed islands and pads that the net area already excludes.
- Ordering one container size the supplier does not sell for that product.
- Ordering a coal tar product where local rules restrict or ban it.
- Leaving the label coverage, coat count, and container breakdown off the order record.
Sources and scope
- SealMaster, Coal Tar Concentrate Pavement Sealer technical data sheet: mixed rate 0.11 to 0.13 gallon per square yard per coat, concentrate estimating rate 100 to 120 square feet per gallon per coat, 2 coats with a third coat on high-traffic areas, 50 degree Fahrenheit minimum, 4-week cure for new asphalt.
- SealMaster, Polymer Modified Coal Tar Sealer (PMCTS) technical data sheet: concentrate estimating rate 85 to 95 square feet per gallon per coat.
- SealMaster, Coal Tar Ready-Mix technical data sheet: ready-mix estimating rate 80 to 95 square feet per gallon per coat.
- SealMaster, Coal Tar Pavement Sealer product page: 50 to 60 square feet per gallon for two coats, 5-gallon pail and 55-gallon drum sizes, 2 coats recommended, 24 hours before traffic.
- NEYRA FAQ via NAC Supply: ready-to-use coverage 70 to 100 square feet per gallon, dilution of ready-to-use product at or below 5%.
- NIST Handbook 44, 2026 Appendix C: square-foot, square-yard, litre, and cubic-metre relationships.
Scope: the formulas convert a stated net area and a stated label coverage into a purchase quantity. The governing product label, supplier terms, local rules, site conditions, and responsible qualified people control the accepted product, coat count, and final order quantity.
Review responsibility: Saleem Sial owns the published calculation, source, and editorial checks. Waseem Sial, External Reviewer and Engineer, remains listed for ongoing external review; no completed external-review date is claimed.
Next, use the measure for asphalt sealcoat guide when the net area is not yet measured, use the sealcoat product guide when the product family is not yet chosen, or return to the Asphalt Calculators hub.
