Asphalt Volume Calculator 2026: ft³, yd³, m³ by Shape
Volume is the second-to-last step before tonnage — once you have it, multiplying by density gives you tons immediately. This calculator handles 4 shapes (rectangle, circle, triangle, multi-section), dual units (imperial and metric), and outputs ft³, yd³, m³ and US tons / metric tonnes simultaneously. Below: shape-by-shape formulas, the loose-vs-compacted gotcha, and worked examples for common project geometries.
Run the asphalt volume calculator
Enter shape and dimensions. The calculator outputs volume in 4 units, plus US tons and metric tonnes at your chosen density (default 145 lb/ft³ HMA).
Volume formulas by shape (with worked examples)
Rectangle / square
Volume (ft³) = length (ft) × width (ft) × depth (ft). Convert depth in inches to feet first: depth (ft) = depth (in) / 12. Example: 20 × 40 ft driveway at 2-inch depth: 20 × 40 × (2/12) = 133.3 ft³ = 4.94 yd³ = 3.77 m³.
Circle
Volume (ft³) = π × radius² × depth (ft). Use radius (= diameter/2), not diameter. Example: 12 ft diameter cul-de-sac (radius 6 ft) at 3-inch depth: 3.14159 × 36 × 0.25 = 28.3 ft³ = 1.05 yd³ = 0.80 m³.
Triangle
Volume (ft³) = 0.5 × base (ft) × height (ft) × depth (ft). For a triangular wedge between two pavement edges. Example: 15 ft base × 25 ft height at 3-inch depth: 0.5 × 15 × 25 × 0.25 = 46.9 ft³ = 1.74 yd³.
Multi-section (L-shape, T-shape, irregular)
Break into rectangular sections, calculate each, sum. The volume calculator on this page accepts up to 10 sections. Example L-shape (driveway with turnaround): main 20 × 30 ft + turnaround 12 × 12 ft, both at 2-inch:
| Section | Dimensions | Area (ft²) | Volume (ft³) | Volume (yd³) |
|---|---|---|---|---|
| Main drive | 20 × 30 ft | 600 | 100.0 | 3.70 |
| Turnaround pad | 12 × 12 ft | 144 | 24.0 | 0.89 |
| Total | L-shape | 744 | 124.0 | 4.59 |
Loose vs compacted: the 5% gotcha
Asphalt volume changes between loose (right out of the truck) and compacted (in-place after rolling). Compacted is what your calculator math gives you. Loose is what you might see on a plant invoice if it sells by the yard.
| State | Density (lb/ft³) | Volume per ton (ft³) | Volume per ton (yd³) |
|---|---|---|---|
| Compacted (in-place) | 145 | 13.79 | 0.510 |
| Loose (truck-state) | 138 (~5% lower) | 14.49 | 0.537 |
| Difference | 5% | +0.70 | +0.027 |
Most US plants sell by ton, not by yard, so the loose-compacted distinction usually doesn’t bite. UK plants more commonly sell by m³ loose; if buying there, add 5% to the compacted m³ math. Full conversion details are in the cubic yards to tons reference.
Unit conversions: ft³, yd³, m³, gallons
| From | To ft³ | To yd³ | To m³ | To US gal |
|---|---|---|---|---|
| 1 ft³ | 1 | 0.0370 | 0.02832 | 7.481 |
| 1 yd³ | 27 | 1 | 0.7646 | 201.97 |
| 1 m³ | 35.31 | 1.308 | 1 | 264.17 |
| 1 US gal | 0.1337 | 0.00495 | 0.00379 | 1 |
Asphalt is rarely measured in gallons (it’s a solid not a liquid), but the conversion factor is occasionally useful when comparing sealcoat or liquid binder quantities. For sealcoat math, see the driveway sealing calculator.
Volume to tonnage shortcuts for common projects
| Project | Shape | Volume (ft³) | Volume (yd³) | US tons |
|---|---|---|---|---|
| 2-car driveway, 2-in | 20 × 40 ft | 133.3 | 4.94 | 9.66 |
| 3-car driveway, 2-in | 30 × 40 ft | 200.0 | 7.41 | 14.50 |
| RV pad, 3-in | 15 × 35 ft | 131.3 | 4.86 | 9.52 |
| 20-stall lot, 3-in | 5,400 ft² | 1,350 | 50.0 | 97.9 |
| Cul-de-sac, 3-in | 30 ft diameter | 176.7 | 6.54 | 12.8 |
| 1-lane-mile road, 4-in | 63,360 ft² | 21,120 | 782 | 1,531 |
For automatic tons-with-waste output and per-ton cost ranges by region, use the asphalt tonnage calculator or asphalt cost calculator.
Asphalt volume FAQ
How do I measure depth in cubic feet?
Depth doesn’t go in cubic feet — it’s linear (feet or inches). Cubic feet is the unit of volume that results from multiplying length × width × depth. The conversion that trips people up: most asphalt depth specs are in inches (2", 3"), but length and width are in feet, so convert depth: depth in ft = depth in inches / 12. So 2-inch = 0.167 ft.
How do I calculate volume for a sloped or crowned area?
For slopes under 5%: use the plan-view dimensions (ignore the slope). For 5-15% slopes: multiply plan-view area by 1.01-1.03. For 15-25%: multiply by 1.03-1.08. For steeper, calculate the slope length using Pythagoras. Crown adjustment (the slight arch in roadway center): on roads with 2-3% crown, add 1-2% to volume math. The full method for grade/crown adjustment is in the calculation methodology.
How is volume different from area?
Area is 2-dimensional (ft²): how much surface you’re paving. Volume is 3-dimensional (ft³): how much material occupies that surface at a given depth. Tonnage depends on volume (multiplied by density). The asphalt industry tends to think in area × depth rather than directly in volume, but the math collapses to the same answer. For pure area-to-tonnage shortcuts at standard depths, see the square feet to tons reference.
What's the volume of 1 ton of asphalt?
13.79 ft³ (0.510 yd³ or 0.390 m³) of compacted standard HMA at 145 lb/ft³. Loose volume (truck state) is about 14.49 ft³ per ton. For recycled millings at 120 lb/ft³: 16.67 ft³ per ton. For SMA at 150 lb/ft³: 13.33 ft³ per ton. Full density-by-mix-type variants are in the asphalt weight calculator.
Why is volume math useful if I can just calculate tons directly?
Three reasons: (1) plant tickets sometimes quote yards instead of tons — you need volume to verify; (2) trucks are sized in cubic yards of capacity, not in tons; (3) structural design uses volume for loading calcs. Most contractors think in tons because that’s what they pay for, but the volume number tells you whether you can fit the order in one truck or need two.