Asphalt (also called bitumen) is a dark, sticky, and highly viscous liquid or semi-solid form of petroleum. In road construction, asphalt is mixed with aggregates (crushed stone, gravel, and sand) to create asphalt concrete, commonly known as "asphalt pavement." For a detailed overview of different asphalt types and their applications, see our types of asphalt guide. A typical asphalt mixture contains:
This mixture is heated, laid down on prepared surfaces, and compacted to create durable surfaces for roads, driveways, parking lots, and other paved areas.
Accurate asphalt calculations are crucial for several reasons:
Helps create accurate project quotes and budgets, preventing cost overruns.
Ensures you order the right amount of asphalt, avoiding waste or shortages.
Determines how many truckloads will be needed to deliver the asphalt to your site.
Whether you're a DIY homeowner planning a driveway project or a contractor preparing a bid, knowing how to calculate asphalt requirements accurately will save you time, money, and headaches.
Follow these steps to calculate how much asphalt you need for your project:
Measure the length and width of the area to be paved.
Area = Length × Width
(in square meters or square feet)
Decide how thick the asphalt layer should be (typically 2-4 inches or 5-10 cm).
Thickness (m) = Thickness (cm) ÷ 100Thickness (ft) = Thickness (in) ÷ 12
Multiply the area by the thickness to find the volume.
Volume = Area × Thickness
(in cubic meters or cubic feet)
Convert volume to weight using the density of asphalt.
Weight (kg) = Volume (m³) × 2322Weight (lb) = Volume (ft³) × 145
Note: 2322 kg/m³ (145 lb/ft³) is the typical density of hot mix asphalt. For more information on asphalt density and unit weight, see our unit weight of asphalt guide.
Convert the weight to tons for ordering purposes.
Metric Tons = Weight (kg) ÷ 1000US Tons = Weight (lb) ÷ 2000
Metric Units:
Tons = (Length (m) × Width (m) × Thickness (cm) ÷ 100) ×
2.322
Imperial Units:
Tons = (Length (ft) × Width (ft) × Thickness (in) ÷ 12) × 145 ÷
2000
Let's calculate how much asphalt you need for a driveway with these dimensions:
Step 1: Calculate the area
Area = 10m × 5m = 50 m²
Step 2: Convert thickness to meters
Thickness = 5cm ÷ 100 = 0.05m
Step 3: Calculate volume
Volume = 50m² × 0.05m = 2.5 m³
Step 4: Calculate weight in kg
Weight = 2.5m³ × 2322 kg/m³ = 5,805 kg
Step 5: Convert to tons
Tons = 5,805 kg ÷ 1000 = 5.805 metric tons
Result: You need approximately 5.8 metric tons of asphalt for this driveway.
Different types of asphalt have different densities, which affects how much material you'll need. Understanding the differences between asphalt and blacktop can also help you choose the right material for your project:
| Asphalt Type | Density (kg/m³) | Density (lb/ft³) | Common Applications |
|---|---|---|---|
| Hot Mix Asphalt (HMA) | 2322 | 145 | Roads, highways, driveways |
| Cold Mix Asphalt | 2000-2200 | 125-137 | Patching, temporary repairs |
| Recycled Asphalt Pavement (RAP) | 1800-2200 | 112-137 | Base layers, mixed with new asphalt |
| Porous/Open-Graded Asphalt | 1900-2100 | 118-131 | Drainage areas, parking lots |
| Stone Mastic Asphalt (SMA) | 2350-2450 | 147-153 | High-traffic roads, durability |
Note: Always confirm the specific density with your asphalt supplier, as it can vary based on the aggregate mix and local materials.
While the manual calculations above are useful to understand the process, we offer free online calculators to make your job easier:
Our main calculator for all asphalt calculations including volume, weight, and cost estimates.
Use Calculator →
Specialized calculator for driveway projects with cost breakdown.
Use Calculator →
Focus specifically on calculating tons of asphalt needed for your project.
Use Calculator →
Focus specifically on calculating blacktop tonnage and cost for paving.
Use Calculator →
Pro Tip: Our calculators automatically handle all the conversions and density calculations for you, saving time and reducing the chance of errors.
To calculate asphalt tonnage, first determine the volume by multiplying length × width × thickness. Then multiply this volume by the density of asphalt (typically 2322 kg/m³ or 145 lb/ft³). Finally, convert to tons by dividing by 1000 (for metric tons) or 2000 (for US tons).
One ton of asphalt typically covers about 80 square feet (7.4 square meters) at a 2-inch (5 cm) thickness. For a 3-inch (7.5 cm) thickness, one ton covers approximately 55 square feet (5.1 square meters). Coverage varies based on the specific density of the asphalt mix and the compaction rate.
Volume measures the physical space the asphalt occupies (cubic meters or cubic yards), while weight measures the mass of the material (tons or kilograms). You convert from volume to weight by multiplying by the density of asphalt. Contractors typically order asphalt by weight (tons), but calculate project requirements by volume.
Recommended asphalt thickness varies by application:
These thicknesses are for the asphalt layer only and assume a proper base layer underneath.
The standard unit weight (density) of hot mix asphalt is approximately:
By following these calculations and tips, you'll be able to accurately estimate the amount of asphalt needed for your project, helping you budget appropriately and avoid costly over-ordering or shortages.