An estimate is only useful if you can trust it, so this page lists exactly how our calculators turn your measurements into tons, cubic yards, gallons and dollars. Nothing is hidden in the code: every result on the site also shows a "How we got this" line with the numbers it used, and you can repeat any calculation by hand with the formulas below.
Our Principles
- Show the working. Every calculator prints the formula and intermediate values next to the result.
- Use published reference values. Default densities and conversion factors come from industry bodies and standards organizations, cited below. Where values vary by product or region, we give a range and let you override the default.
- Separate quantity from price. Material quantities follow from physics and are reliable. Prices change by region and month, so we present them as ranges with the date they were checked and ask you to enter your own quote.
- Don't double-count. For example, asphalt tonnage uses compacted, in-place density, so we never add a separate compaction percentage to the tons (see below).
- Estimates, not engineering. Our tools are for planning, budgeting and checking quotes. Structural pavement design for roads and commercial lots should be done by a qualified engineer.
Asphalt Quantity
All asphalt calculators follow the same chain: area → volume → weight.
- Area. Rectangle = length × width. Circle = π × radius². Triangle = ½ × base × height. Multiple sections are added together.
- Volume. Area × compacted thickness. Thickness in inches is divided by 12 to get feet (or centimeters by 100 to get meters). Cubic feet ÷ 27 = cubic yards.
- Weight. Volume × density. In US units, pounds ÷ 2,000 = short tons. In metric, kilograms ÷ 1,000 = tonnes.
- Order quantity. Weight × (1 + waste %). The main calculator's Simple mode adds 5%; Advanced mode lets you choose.
- Truckloads. Order quantity ÷ truck capacity, rounded up. Default 20 tons, a typical legal load for a tri-axle dump truck.
Shortcut used on the site: tons = square feet × inches × 0.00604. This is 145 lb/ft³ ÷ 12 ÷ 2,000. In square yards it becomes about 110 lb per square yard per inch (145 × 0.75 = 108.75, conventionally rounded to 110).
On this page
Default Values
| Value | Default | Basis |
|---|---|---|
| Hot mix asphalt, in-place density | 145 lb/ft³ (2,322 kg/m³) | Midpoint of the Asphalt Institute's typical 142 to 148 lb/ft³ |
| Spread rate | 110 lb/SY-in | Density × 0.75, common estimating convention |
| Warm mix / cold mix / porous | 143 / 130 / 125 lb/ft³ | Approximate planning values; confirm with your supplier |
| Waste allowance | 5% | Common contractor practice of 5 to 10% |
| Roll-down (loose to compacted) | 25% | Field rule of thumb of about 1/4 inch per inch; affects loose depth only |
| Crushed stone base | 1.5 tons per loose cubic yard, plus 25% for compaction | Typical supplier figures range from about 1.35 to 1.7 t/yd³ loose; the 25% allowance follows common practice for dense-graded base |
| Truck capacity | 20 tons | Typical tri-axle legal payload of roughly 18 to 22 tons for hot mix |
| Ton / tonne | 2,000 lb / 1,000 kg | NIST conversion tables |
Specialized tools (sealcoat, cold patch, millings, gravel base) cite the coverage and density figures they use on their own pages.
Why We Don't Add Compaction to Tonnage
Some calculators add 15 to 25% to the tons "for compaction". That is a double count. Asphalt is bought by weight, and the density we use is the density after rolling. The paver lays the mix loose, roughly a quarter deeper than the finished mat, and the rollers squeeze the same tons into a thinner layer. So compaction changes the loose depth, which we report separately, but not the weight you order. Extra material for an uneven base, edges and spillage is real, and the waste allowance is where it belongs.
Loose granular materials such as crushed stone and millings are different: they are often sold by loose volume or loose weight, and they compact under a roller. Those calculators include a compaction allowance and explain it on the page.
Cost Figures
Cost tools multiply quantities by the unit prices you enter. Default prices and the ranges in our articles come from published US cost guides and supplier information that we review when we update a page; the review month is shown at the bottom of each page. Asphalt prices track crude oil and local demand and can move noticeably within a season, so always replace defaults with a current local quote.
How We Check Results
- Every worked example on the site is recalculated independently from the formulas above before publishing.
- Each calculator is tested in a browser with known inputs (for example, 40 × 12 ft at 3 in must return 8.70 tons) whenever the code changes.
- Imperial and metric modes are checked against each other: switching units converts your inputs so the same project gives the same weight.
Corrections and Updates
If you think a number on this site is wrong, email asphaltcalculator@gmail.com with the page and the figure. We review every report, fix confirmed errors, and update the "Last updated" date on the page. Material changes to formulas or defaults are also noted on this page.
- October 2026: Removed the compaction percentage from asphalt tonnage in the main calculator and replaced it with a roll-down field that reports loose lay depth. Added mix types, gravel base, truckloads, coverage per ton and shareable links. Corrected rounding in two worked examples.
Sources
- Asphalt Institute, Engineering FAQs: Asphalt Pavement Thickness and Mix Design.
- Asphalt Institute, Glossary of Terms.
- NIST Office of Weights and Measures, Approximate Conversions from U.S. Customary Measures to Metric.
- National Asphalt Pavement Association, Reclaimed asphalt pavement recycling.
Last updated: October 2026 · How we calculate