A 4-inch layer of millings on a 600 ft² driveway weighs about 11.2 tons. Order 8 and the surface is thin in places. Order 14 and 3 tons sit in the yard.
This asphalt millings calculator turns area, depth and density into tons or tonnes and cubic yards of recycled asphalt pavement (RAP). It works in feet and inches or in metres and millimetres. You can enter length and width, or type the area if you already know it.
What Are Asphalt Millings?
Asphalt millings are the material left when a milling machine grinds old asphalt off a road, parking lot or driveway. The trade calls it RAP, short for reclaimed asphalt pavement. Other names are recycled asphalt and crushed asphalt.
RAP is roughly 93% to 97% aggregate and 3% to 7% old asphalt binder by weight. Particles run from about 0.3 to 1.5 inches (10 to 40 mm). RAP is free draining and not frost susceptible, and agencies use it in bases, shoulders and new asphalt mixes. Stockpiles often hold 5% to 8% moisture by weight, which matters when you order by the ton.
How to Use the Asphalt Millings Calculator
- 1Choose Imperial (feet and inches) or Metric (metres and millimetres).
- 2Choose Length × Width, or choose Enter Area Directly if you know the area.
- 3Enter the depth of the finished, compacted layer.
- 4Check the RAP density. The default is 1,800 kg/m³ (about 112.4 lb/ft³).
- 5Click Calculate Millings to get tons or tonnes and cubic yards.
For an irregular area, split it into rectangles, run each one and add the results. For two layers, run the tool once per layer.
Asphalt Millings Formulas
Imperial Units
Volume (ft³) = Area (ft²) × Depth (in) ÷ 12
Cubic yards = Volume (ft³) ÷ 27
Tons = Volume (ft³) × Density (lb/ft³) ÷ 2,000
Metric Units
Volume (m³) = Area (m²) × Depth (m)
Tonnes = Volume (m³) × Density (kg/m³) ÷ 1,000
Convert depth before multiplying: millimetres ÷ 1,000 gives metres.
Constants & Conversions
| Conversion | Value |
|---|---|
| 1 yd³ | 0.7646 m³ |
| 1 short ton | 907.185 kg |
| 1 tonne | 1.1023 short tons |
| lb/ft³ × 16.0185 | kg/m³ |
At 1,800 kg/m³, one inch of depth over 1,000 ft² weighs about 4.68 tons and fills about 3.09 yd³.
Which Density Should You Use?
Published values depend on the source and the RAP material:
- FHWA Guidance gives a compacted unit weight of 1,600 to 2,000 kg/m³ (100 to 125 lb/ft³), and notes that finer-crushed RAP compacts denser.
- A New York City DOT Fact Sheet lists milled RAP at 120 to 140 lb/ft³.
- The calculator default of 1,800 kg/m³ sits squarely inside the FHWA range. Ask your supplier for a number when you can.
| Density Level | kg/m³ | lb/ft³ | Short tons per yd³ |
|---|---|---|---|
| Low | 1,600 | 99.9 | 1.35 |
| Default | 1,800 | 112.4 | 1.52 |
| High | 2,000 | 124.9 | 1.69 |
Moisture changes the weight on the scale. At 8% moisture, a ton of delivered RAP holds about 0.92 tons of dry material. If your supplier sells by weight, ask whether the density they quote is wet or dry.
Compacted Depth vs Loose Depth
Weight stays the same before and after compaction. Volume changes. A layer spread loose shrinks when you roll it.
The calculator estimates the weight and volume of the finished, compacted layer. Use the depth you want after rolling.
For spreading, supplier guidance often suggests about 1.3 to 1.5 times the finished depth. A 4-inch compacted layer then needs about 5.3 to 6 inches spread loose. Confirm the figure with your supplier, because gradation, moisture and equipment all change it. Cubic yards of loose material delivered will exceed the compacted cubic yards the calculator shows.
Worked Examples
Driveway, 4 inches compacted
The driveway is 12 ft × 50 ft. Density is 1,800 kg/m³.
Area: 600 ft²
Volume: 600 × (4 ÷ 12) = 200 ft³, or 7.41 yd³
Weight: 200 × 112.4 = 22,474 lb
Result: 11.24 tons (10.19 tonnes)
Spread about 5.3 to 6 inches loose to reach 4 inches compacted.
Driveway with a parking pad
A strip is 10 ft × 100 ft. A pad is 30 ft × 30 ft. Depth is 4 inches compacted.
Area: 1,000 + 900 = 1,900 ft²
Volume: 1,900 × (4 ÷ 12) = 633.3 ft³, or 23.46 yd³
Result: 35.59 tons
Metric parking area
The area is 200 m². Depth is 100 mm. Density is 1,800 kg/m³.
Volume: 200 × 0.10 = 20 m³, or 26.16 yd³
Result: 36 tonnes (about 39.7 short tons)
Road shoulder
A 2 km shoulder is 1.5 m wide and 150 mm deep.
Area: 2,000 × 1.5 = 3,000 m²
Volume: 3,000 × 0.15 = 450 m³
Result: 810 tonnes
Density changes the order
Take the driveway from Example 1 (200 ft³ of compacted millings):
1,600 kg/m³: 9.99 tons
1,800 kg/m³: 11.24 tons
2,000 kg/m³: 12.49 tons
The spread is about 11% either way. A supplier's density figure removes that uncertainty.
Cubic yards to tons
An order of 10 yd³ at 1,800 kg/m³ weighs 10 × 1.52 = 15.2 short tons. The same order at 1,600 kg/m³ weighs 13.5 tons.
Asphalt Millings Charts
US units (1,800 kg/m³, 112.4 lb/ft³)
| Compacted depth | Tons / 1,000 ft² | yd³ / 1,000 ft² | Area / 1 ton |
|---|---|---|---|
| 2 in | 9.36 | 6.17 | about 107 ft² |
| 3 in | 14.05 | 9.26 | about 71 ft² |
| 4 in | 18.73 | 12.35 | about 53 ft² |
| 6 in | 28.09 | 18.52 | about 36 ft² |
Metric units (1,800 kg/m³)
| Compacted depth | Tonnes / 100 m² | Area / 1 tonne |
|---|---|---|
| 50 mm | 9.0 | about 11.1 m² |
| 75 mm | 13.5 | about 7.4 m² |
| 100 mm | 18.0 | about 5.6 m² |
| 150 mm | 27.0 | about 3.7 m² |
For a different density, scale the result. A 1,600 kg/m³ material weighs about 11% less than these figures.
Common Uses and Depths
Driveways. Many suppliers commonly recommend 3 to 4 inches compacted over a solid base. Compaction is what holds the surface together, so plan for a roller or plate compactor.
Parking areas. Light-duty parking commonly uses 4 inches or more. Heavier use needs more depth.
Road base and sub-base. RAP appears in base courses and sub-bases, often blended with natural aggregate. Follow the project specification for depth and blend.
Shoulders and farm roads. RAP reduces dust and erosion on unpaved shoulders and access tracks.
Fill and grading. Agencies report uses such as ramps, backfill and trench work. Some agencies advise caution near water and drainage, so check local rules.
What Changes the Quantity
- Depth. Weight rises in direct proportion to depth. A 4-inch layer that averages 4.5 inches uses 12.5% more material.
- Density. Gradation, binder content and moisture all move it. See the density table above.
- Moisture. Wet RAP weighs more per cubic foot, and a ton of it contains less dry material.
- Base condition. Low spots and ruts take extra material to reach the planned depth.
- Edges. Add width where you taper at the edge or tie into a street.
- Waste. Allow a margin for uneven ground and spillage. Your supplier or contractor can tell you what is normal.
Millings vs New Asphalt
RAP works well on driveways, light parking areas, bases and shoulders. New hot mix asphalt uses fresh binder and a controlled gradation, which gives better strength and smoothness under heavy traffic. For new asphalt weights, use the asphalt tonnage calculator.
The old binder in RAP is not counted as new binder in a mix design. To work out binder in new asphalt, use the bitumen calculator. If you want to bond a new layer over milled pavement, the tack coat calculator gives the emulsion quantity. For budgets, see the asphalt driveway cost calculator.
Common Mistakes
- ✕
Entering the loose depth. The calculator expects the finished, compacted depth.
- ✕
Entering lb/ft³ without unit check. The field uses kg/m³. Typing 112 yields results 16 times too low (our tool auto-detects values under 300 to protect you).
- ✕
Mixing tons and tonnes. One tonne is 1.1023 US tons, a 10% gap.
- ✕
Skipping moisture. Ask whether your supplier's density is wet or dry.
- ✕
Measuring only the main strip. Include pads, aprons and turnarounds.
- ✕
Ordering by cubic yard without checking the basis. Loose and compacted cubic yards differ by 30% or more.
Frequently Asked Questions
Q: How many tons of millings do I need for a driveway?
A 12 ft × 50 ft driveway at 4 inches compacted needs about 11.2 tons at 1,800 kg/m³.
Q: How many square feet does 1 ton of millings cover?
About 53 ft² at 4 inches compacted, 71 ft² at 3 inches and 107 ft² at 2 inches.
Q: How do I convert cubic yards of millings to tons?
Multiply cubic yards by about 1.52 short tons per cubic yard at 1,800 kg/m³. That equals 1.38 metric tonnes per cubic yard.
Q: What density should I use for RAP?
FHWA guidance gives 1,600 to 2,000 kg/m³ (100 to 125 lb/ft³) for compacted RAP. The calculator defaults to 1,800 kg/m³. Use your supplier's number if you have one.
Q: How deep should millings be for a driveway?
Many suppliers recommend 3 to 4 inches compacted over a solid base. Heavier use needs more.
Q: How much loose material do I need for a 4-inch compacted layer?
Supplier guidance often suggests spreading about 1.3 to 1.5 times the finished depth, so about 5.3 to 6 inches. Confirm with your supplier.
Q: What are asphalt millings made of?
About 93% to 97% aggregate and 3% to 7% old asphalt binder by weight.
Q: Are millings as good as new asphalt?
RAP suits driveways, light parking, bases and shoulders. New asphalt performs better on high-traffic surfaces.
Conclusion
An asphalt millings calculator gives you a planning weight in seconds. Enter the compacted depth, check the density with your supplier and allow for moisture and edges. Then confirm whether your quote is in tons, tonnes or loose cubic yards before you order.
Results are estimates for planning only. Confirm quantities and depths with your supplier or contractor.