How to Calculate Asphalt for Your Project
Determining how much asphalt you need can be tricky. If you order too much then you risk overspending and if you order too little then you'll hold up the project. Here's how to work out the correct amount for a driveway, parking lot or road.
Step 1: Measure the Area
First, determine the length and width of the surface in feet (or meters). Rectangle-shaped surfaces are simple to work out. For irregular shapes, divide the surface into smaller geometric shapes -rectangles, triangles, circles- and work them out individually and sum the total.
Area formula for a rectangle: Area = Length ร Width
Area formula for a circle: Area = ฯ ร Radiusยฒ
Area formula for a triangle: Area = 0.5 ร Base ร Height
Step 2: Determine the Thickness
The thickness of your asphalt layer depends on the intended use. Here are the recommended thicknesses:
- Driveways (light traffic): 2โ3 inches
- Parking lots (medium traffic): 2.5โ4 inches
- Roads (heavy traffic): 4โ6 inches or more
- Pathways and walkways: 1.5โ2 inches
In cold climates, increase the thickness by 10-15% for freeze-thaw action. In hot climates, increase by 10% for rutting due to heat softening.
Step 3: Calculate Volume
Once you have the area and thickness, calculate the volume:
Volume (cubic feet) = Area (sq ft) ร Thickness (inches) รท 12
Volume (cubic yards) = Volume (cubic feet) รท 27
Step 4: Convert Volume to Weight
Asphalt is ordered by weight (tons), not volume. To convert:
Weight (lbs) = Volume (cubic feet) ร Density (lbs/cu ft)
Weight (tons) = Weight (lbs) รท 2,000
HMA has a density of about 145LBS per ft 3 (2,322 KG/m). Warm mix and cold mix asphalt have a density around 140LBS per ft 3 (2,243 KG/m).
Step 5: Add Wastage Factor
Always order 5-10% more material than calculated. This accounts for:
- Material lost during transport and handling
- Compaction (asphalt compresses during rolling)
- Irregular surfaces requiring extra material
- Edges and borders needing additional coverage
Understanding Asphalt Types
Hot Mix Asphalt (HMA)
Hot mix asphalt is the typical pavement in the industry. It is created at 300-350F (150-175C) and needs to be laid and compacted while it is still hot. HMA is the most durable and appropriate for roads, highways, driveways, and parking lots. Cost averages from $80 to $160 per ton.
Warm Mix Asphalt (WMA)
Warm mix asphalt is made at lower temperatures, 200-275F / 95-135C, which limits the amount of fuel and emissions released during production, by as much as 30 percent. It performs similarly to HMA in most situations and is becoming more widely used for urban paving, residential roads, and projects that have a heightened impact on the environment. Warm mix asphalt costs $85-165 per ton.
Cold Mix Asphalt
Cold mix: is seen to self-heal at the laying temperature so well suited to emergency repairs, pothole filling and minor patching works. It is not as strong as hot or warm mix and will not be suited to wearing courses on heavily trafficked roads. Approximately $50 to $100 / ton. Col mix can be bought from many hardware stores.
Asphalt Cost Factors
The total cost of an asphalt paving project includes more than just the material. Here is a typical cost breakdown:
- Material (40-50%): The asphalt itself, priced per ton
- Labor (25-35%): Paving crew costs, typically $3-$5 per square foot
- Equipment (10-15%): Paver, roller, and truck rental
- Delivery (5-10%): Transport from the asphalt plant to your site
We give you an all-inclusive cost estimate that accounts for all of these components of labor and supplies.
Tips for Accurate Estimates
- Measure twice: The greatest error we experience in trial is measurement. Try to judge time more than once and take the mean.
- Take into account the base: An appropriate sub-base is necessary. Remember to take in consideration gravel or aggregate base materials in your project planning.
- Verify neighborhood prices. Asphalt prices can differ across cities and regions. Speak to your local supplier for details of their current prices.
- Drainage plan: Knowing how to drain properly as it prevents any water damage. Consider the cost of slope and drainage preparation in your budget.
- Collect multiple quotes: For contractor projects, use at least 3 quotes to ensure competitive rates.
Common Mistakes to Avoid
- Ignoring the wastage factor: Always load in 5-10% extra than what you've calculated. You run out when paving, your seams will be shot and it will be weak where you stop.
- Inaccurate using of density: The densities of various asphalt types are not the same. Incorrect density application may result in a big error.
- Overlooking the sub base: The infra layer is equally vital as the asphalt floor. Mishandling it results in early collapse.
- Paving in poor weather conditions: Asphalt must be laid at a temperature of at least 50F (10C). Cold weather inhibits compacting of the asphalt.
- Selecting an incorrect thickness: Too thin can cause pothole/crack issues. Use our recommendation engine to find the right thickness.