How this calculator works
The converter takes a density in lb/ft³ or kg/m³ and returns the other unit using the exact factor 1 lb/ft³ = 16.0185 kg/m³. That is the whole conversion — but the reason it matters is what you do next: density is the multiplier that turns a volume into a weight, and asphalt is bought by weight.
Once you have a density in lb/ft³, use it in the asphalt weight calculator to convert a known volume to tons, or in the asphalt tonnage calculator to go straight from area and thickness to an order.
The formula
Density (kg/m³) = Density (lb/ft³) × 16.0185
Density (lb/ft³) = Density (kg/m³) ÷ 16.0185
Weight (lb) = Volume (cu ft) × Density (lb/ft³)
Example: 145 lb/ft³ × 16.0185 = 2,323 kg/m³. The factor is exact because the pound and the meter are defined exactly, so this conversion carries no rounding of its own beyond the digits you keep.
Worked examples
Example 1 — converting the default density to metric
- Density:
- 145 lb/ft³
- Target unit:
- kg/m³
- Apply the factor: 145 × 16.0185 = 2,322.7 kg/m³
- Round: ≈ 2,323 kg/m³
Density: 2,323 kg/m³
This matches the metric value suppliers cite for standard hot mix asphalt.
Example 2 — a supplier quotes 2,350 kg/m³
- Density:
- 2,350 kg/m³
- Target unit:
- lb/ft³
- Divide by the factor: 2,350 ÷ 16.0185 = 146.7 lb/ft³
- Check the range: 146.7 is inside 142–148 lb/ft³
Density: 146.7 lb/ft³
Converting to lb/ft³ lets you drop the figure straight into the tonnage formula, which expects imperial density.
Reference data
| Density (lb/ft³) | Density (kg/m³) |
|---|---|
| 140 lb/ft³ | 2,243 kg/m³ |
| 142 lb/ft³ | 2,275 kg/m³ |
| 145 lb/ft³ | 2,323 kg/m³ |
| 148 lb/ft³ | 2,371 kg/m³ |
| 150 lb/ft³ | 2,403 kg/m³ |
| Density (lb/ft³) | 1 cu yd (lb) | 1 cu yd (US tons) |
|---|---|---|
| 142 lb/ft³ | 3,834 lb | 1.92 tons |
| 145 lb/ft³ | 3,915 lb | 1.96 tons |
| 148 lb/ft³ | 3,996 lb | 2.00 tons |
Key facts
- Standard hot mix asphalt has an in-place density of about 145 lb/ft³, or 2,323 kg/m³.
- The Asphalt Institute gives in-place asphalt unit weight as 142–148 lb/ft³ and recommends 148 PCF for calculations.
- To convert asphalt density, multiply lb/ft³ by 16.0185 for kg/m³; the factor is exact.
- At 145 lb/ft³, one cubic yard of asphalt weighs about 3,915 pounds, or 1.96 US tons.
Who should use this and when
Anyone reconciling a spec against a formula uses this. Estimators convert a supplier's metric density into the lb/ft³ that US tonnage math expects; engineers check that a mix's reported unit weight is inside the expected range. Homeowners rarely need it directly, but it is the value quietly driving every tonnage figure they see. With a density in hand, move to the asphalt volume calculator or the asphalt thickness calculator to build the rest of the estimate.
Tips and common pitfalls
- Do not confuse mix density with compaction. The 142–148 lb/ft³ range is in-place, compacted unit weight — loose mix behind the paver is lighter.
- Keep the units straight. kg/m³ figures are roughly 16 times the lb/ft³ figure; a value near 2,300 is metric, a value near 145 is imperial.
- Aggregate changes the number. Denser aggregate raises unit weight; a higher air-void content lowers it. Prefer the mix design over a generic default.
- Density feeds weight, not area. It only enters once you are turning volume into tons — it has no bearing on the square footage of the job.
Frequently asked questions
What is the standard density of asphalt?+
Standard hot mix asphalt is about 145 lb/ft³ (roughly 2,323 kg/m³). The Asphalt Institute gives an in-place unit weight of 142–148 lb/ft³ and recommends using 148 PCF for calculations; this site defaults to 145 as a mid-range planning value.
How do I convert asphalt density between lb/ft³ and kg/m³?+
Multiply lb/ft³ by 16.0185 to get kg/m³, or divide kg/m³ by 16.0185 to go back. So 145 lb/ft³ × 16.0185 = 2,323 kg/m³. This factor is exact, derived from the definitions of the pound and the meter.
Why does asphalt density matter for a paving estimate?+
Density converts volume into weight, and asphalt is ordered by weight. Weight equals volume times density, so a small change in density moves the tonnage directly — using the right value keeps an order from running short or long.
What density should I use if I do not know my mix?+
Use 145 lb/ft³ as a planning default; it sits mid-range inside the Asphalt Institute's 142–148 lb/ft³ and is accurate enough for estimating. Once you have the mix design or a supplier figure, enter that instead for a tighter number.
What is the density range for asphalt?+
The Asphalt Institute gives an in-place range of 142–148 lb/ft³ (about 2,275–2,371 kg/m³). Reported values vary somewhat with aggregate gradation and air-void content, but staying inside that range keeps a tonnage estimate realistic.
How much does a cubic yard of asphalt weigh?+
At 145 lb/ft³, one cubic yard (27 cubic feet) weighs about 3,915 pounds, or roughly 1.96 US tons. At the top of the range, 148 lb/ft³, it is about 3,996 pounds, or almost exactly 2 tons.
Related Asphalt Tools
Convert asphalt volume to tons using standard density.
Asphalt Thickness CalculatorConvert asphalt thickness from inches to feet and meters.
Asphalt Tonnage CalculatorCalculate required hot mix asphalt tonnage for any paving project.
Asphalt Volume CalculatorCalculate asphalt volume in cubic yards, feet, or meters.
Asphalt Square Footage CalculatorCalculate total project area. Sum multiple rectangular sections.
Asphalt Area CalculatorCalculate the total area of your paving project.
Estimates & assumptions
- Unit conversion is exact: 1 lb/ft³ = 16.0185 kg/m³ (NIST SP 811).
- The 142–148 lb/ft³ in-place range and the 148 PCF calculation value are the Asphalt Institute's; 145 lb/ft³ is this site's mid-range planning default.
- Reported densities vary with aggregate gradation and air-void content; use your mix design where you have it.
- This tool converts density units; it does not perform mix design or measure the density of a specific sample.
Estimates are for planning only. Confirm the density of your specific mix with your supplier before ordering material.