Audit the estimate
Methodology, formulas, and sources
Every output comes from the inputs shown in the calculator. This page documents conversions, defaults, validation, rounding, and what the site deliberately does not infer.
Material formula
- Area: length × width, or a known total area supplied by the user.
- Compacted volume: area × compacted thickness after both values are in compatible units.
- Base weight: compacted volume × compacted mix density.
- Base tonnage: pounds ÷ 2,000 for US short tons; kilograms ÷ 1,000 for metric tonnes.
- Order quantity: base tonnage × (1 + waste percentage ÷ 100).
- Optional material cost: order quantity × the user-entered price per short ton or metric tonne.
Known-volume weight conversion
The asphalt weight workflow starts from compacted volume rather than area and thickness. It converts cubic yards or cubic meters to a common internal volume, multiplies by the user-entered compacted density, then reports pounds, kilograms, short tons, metric tonnes, short tons per cubic yard, and metric tonnes per cubic meter.
It does not add waste, select a mix, or turn the result into an order quantity. Those are separate project decisions.
Density default and its limit
The starting density is 145 lb/ft³ (about 2,323 kg/m³). It is a rounded planning value, not a specification.
- The Asphalt Institute engineering FAQ states that asphalt mixture typically weighs 142–148 lb/ft³ in place and describes the volume × density ÷ 2,000 workflow.
- The EPA cleanup-footprint methodology uses 1.95 short tons per cubic yard for asphalt, equivalent to about 144.4 lb/ft³.
A supplier’s job-mix or measured compacted density should replace the default when available.
Unit conversions
| Conversion | Value used |
|---|---|
| International foot | 0.3048 meter |
| Square meter | 10.7639104167 square feet |
| Inch | 2.54 centimeters |
| Pound | 0.45359237 kilogram |
| Short ton | 2,000 pounds |
| Metric tonne | 1,000 kilograms |
| Cubic yard | 27 cubic feet |
References: NIST Guide to the SI, Appendix B, NIST Handbook 44 Appendix B, and the FHWA conversion table.
Cost formula and factual boundary
The driveway workflow adds material cost, preparation rate × area, paving rate × area, delivery allowance, and one other fixed allowance. Every price starts at zero and comes from the user. The site does not publish or infer a national price.
Cost per square foot or square meter is the user-built total divided by the entered paved area. It describes that scenario only; it is not a market rate or quote.
Validation, boundaries, and rounding
- Inputs and their converted or derived values must remain finite. Each dimension is capped at 1,000,000 ft (304,800 m); area is limited to 0.000001–100,000,000 ft²; known volume is capped at 10,000,000 yd³ equivalent; compacted thickness is limited to 0.001–120 in; density must be 50–250 lb/ft³ equivalent.
- Waste is limited to 0–100%; price and allowance fields reject negative and non-finite values.
- Calculations retain full floating-point precision. The interface rounds only displayed values, generally to two decimals and tonnage to three.
What this methodology cannot decide
The calculator does not design pavement thickness, base, grading, drainage, compaction procedure, mix, reinforcement, edges, or traffic capacity. Those choices depend on site conditions and local requirements and belong with a qualified local professional.