About the Asphalt Millings Calculator
When roads and parking lots are resurfaced, the old asphalt is ground off by a milling machine. The result, asphalt millings or recycled asphalt pavement (RAP), is a mix of crushed stone coated with old asphalt binder. Spread and compacted, millings make a firm, dark driveway or parking surface that costs far less than new paving and is more stable than loose gravel. The leftover binder softens in the heat and helps the pieces stick together, so a millings surface hardens over its first summer.
This asphalt millings calculator works out how many tons you need from the area and the finished compacted depth. It adds a compaction allowance, because millings shrink a lot when rolled, and compares the cost with new hot-mix asphalt for the same area.
How to Use the Asphalt Millings Calculator
Enter the length and width in feet and the compacted depth in inches.
Enter the compaction allowance, usually 20 to 30%.
Optionally enter the millings price and the hot-mix asphalt price per ton.
The Formulas
compacted yd³ = length × width × depth ÷ 324
loose yd³ = compacted yd³ × (1 + allowance)
millings tons = loose yd³ × 1.25
hot-mix tons = compacted yd³ × 2Step-by-Step Example
A 60 × 12 ft driveway, 4 inches compacted, 25% allowance, $20 a ton against $100 hot mix.
compacted 60 × 12 × 4 ÷ 324 = 8.89 yd³
loose 8.89 × 1.25 = 11.11 yd³
tons 11.11 × 1.25 = 13.89 tons → about $277.78
hot mix 8.89 × 2 = 17.78 tons → $1,777.78How Millings Compact
Loose millings from a truck contain a lot of air. Rolling them with a heavy vibratory roller, or at least a plate compactor, squeezes them down by around a quarter. Compaction works best on a warm day when the old binder is soft, or when the millings are damp. Some contractors spray a light coat of asphalt emulsion, called tack or a chip seal, over the compacted millings to bind the surface and reduce loose stones. Without it, the surface still hardens over time as traffic and sun work on it.
Building a Millings Driveway
Start with a firm base. On well-drained, stable ground millings can go straight onto compacted subsoil; on soft clay or wet ground, lay 4 to 6 inches of compacted crusher run first. Spread the millings in lifts of about 2 to 3 inches, compacting each one, and crown the surface so water runs off to the sides. Edges ravel faster than the middle, so many owners add timber, stone or concrete edging. A finished depth of 3 to 4 inches is typical for a residential driveway.
Millings Versus Gravel and Hot Mix
Compared with gravel, millings stay in place better, produce less dust and do not spray stones when driven on, though they cost a little more in some areas. Compared with hot-mix asphalt, millings are much cheaper and can be laid by a homeowner with a rented compactor, but they never form a smooth, sealed surface, and potholes need occasional patching. Hot mix is also denser, about 2 tons per compacted yard, against roughly 1.25 tons per loose yard of millings.
Environmental Notes
Recycling asphalt keeps it out of landfill and reduces the need for new stone and oil. In some places, rules restrict the use of millings near wells, streams and wetlands because runoff can carry small amounts of oil-based compounds, especially when the material is fresh. Check local regulations, and avoid using millings where they would drain directly into water.
Ordering
Millings are sold by paving contractors and asphalt plants, often by the ton, and supply varies with the road-building season. Quality varies too; ask for screened millings without large chunks, dirt or debris. As with any bulk material, plan a firm spot for delivery and a route that the truck will not damage.
Maintaining a Millings Surface
A millings driveway needs little care, but a few habits keep it in good shape. Fill potholes as soon as they appear with a shovel of fresh millings, tamped down hard, before water enlarges them. Re-grade and re-roll the surface every few years if ruts develop, adding a thin top-up layer where needed. Keep gutters and downspouts from discharging onto the drive, and maintain the crown so water does not stand on it. In snowy areas, set a plough blade slightly high so it does not tear up the surface.
Estimating Time and Equipment
A two-person crew with a skid steer and a vibratory roller can spread and compact a typical driveway in a day. With only a plate compactor and wheelbarrows, allow two or three days, and lay thinner lifts so each one compacts fully. Rental shops hire walk-behind rollers by the day.
Understanding Your Result
The headline gives the tons of millings.
The volume line shows the compacted and loose cubic yards.
The cost line multiplies the tons by your price.
The versus new asphalt line compares the cost of hot mix.
When Should You Use This Calculator?
Use it when planning a millings driveway, parking pad or farm lane.
Use it to compare the cost of millings with new paving.
Use it to check a supplier's tonnage estimate.
Common Mistakes
Ordering the compacted volume. Allow 20 to 30% for compaction.
Skipping the base on soft ground. Millings rut without support.
Compacting in cold weather. Warmth helps the binder bond.
Using millings near water. Check local restrictions.