Asphalt Calculator
Calculate how many tons of asphalt you need for a driveway or lot from its length, width and depth — with an optional cost estimate. Uses the standard area × depth × density ÷ 2000 tonnage formula.
Updated 2026-06-09 · Free · No sign-up · Runs privately in your browser
What is an asphalt calculator?
An asphalt calculator estimates how many tons of asphalt you need to pave an area to a given depth. Because asphalt is sold by weight rather than volume, the tool converts your length, width and thickness into a tonnage you can order from the plant, plus an optional material cost.
This calculator covers the asphalt (blacktop) wearing course only. The compacted gravel base underneath is a separate material and is not included in the result — see the note below.
How is asphalt tonnage calculated?
Tonnage is the paved volume multiplied by the asphalt density, converted from pounds to US tons. The exact formula the calculator uses is:
tons = length × width × (depth ÷ 12) × density ÷ 2000
All dimensions are in feet, so the depth in inches is divided by 12 to convert it to feet. Density defaults to 145 lb/ft³ for compacted hot-mix asphalt, and dividing by 2,000 converts pounds into US (short) tons. The intermediate volume is shown in cubic feet.
What are some worked examples?
Below are two examples you can reproduce exactly in the calculator.
Example 1 — a residential driveway, 50 ft × 10 ft at 3 inches:
- Volume = 50 × 10 × (3 ÷ 12) = 125 ft³
- Weight = 125 × 145 = 18,125 lb → 18,125 ÷ 2,000 = 9.06 tons
- At $120 per ton, material cost ≈ 9.0625 × $120 = $1,088
Example 2 — a parking pad, 40 ft × 20 ft at 2 inches:
- Volume = 40 × 20 × (2 ÷ 12) = 133.3 ft³
- Weight = 133.3 × 145 = 19,333 lb → ÷ 2,000 = 9.67 tons
- At $130 per ton, material cost ≈ 9.67 × $130 = $1,257
A common two-car pad of 24 ft × 24 ft at 3 inches works out to 144 ft³ and 10.44 tons — handy for sanity-checking your own numbers.
How much asphalt do I need per 100 sq ft?
Use this table for quick estimates at 145 lb/ft³. Multiply the tons figure by your area in hundreds of square feet (for example, 600 sq ft at 3 in = 6 × 1.81 = 10.86 tons).
| Depth | Volume per 100 sq ft | Tons per 100 sq ft | Approx. coverage per ton |
|---|---|---|---|
| 1.5 in | 12.5 ft³ | 0.91 | ~110 sq ft |
| 2 in | 16.7 ft³ | 1.21 | ~83 sq ft |
| 2.5 in | 20.8 ft³ | 1.51 | ~66 sq ft |
| 3 in | 25.0 ft³ | 1.81 | ~55 sq ft |
| 4 in | 33.3 ft³ | 2.42 | ~41 sq ft |
What is asphalt tonnage used for?
The most common use is ordering hot-mix asphalt for a driveway, parking lot, footpath or road overlay. Knowing the tonnage in advance lets you:
- Get accurate quotes from paving plants, which price by the ton.
- Avoid running short mid-pour, which leaves a cold joint if a second truck is delayed.
- Compare the cost of 2 in versus 3 in builds before committing.
- Budget materials separately from base prep, grading and labour.
For sub-base aggregate under the asphalt, pair this with the gravel calculator, and explore more building estimators on the construction tools category page.
Tips and common mistakes
- Order 5–10% extra. Loose mix compacts when rolled, and you lose material to edges, waste and an uneven sub-base. The geometry gives the minimum, not the delivered amount.
- Use your plant’s density. Mixes vary from roughly 140 to 150 lb/ft³ depending on aggregate; override the 145 default when you have a real number.
- Match your units. Length and width are in feet but depth is in inches — entering depth in feet by mistake will overstate tonnage twelve-fold.
- Split irregular areas into rectangles, calculate each, and add the tons together.
- Account for two lifts. A 4-inch driveway is often laid as two 2-inch courses; the total tonnage is the same, but plan delivery accordingly.
Limitations and accuracy notes
This calculator gives a material estimate only. It assumes a uniform depth across a rectangular area and a single density, and it does not include the gravel base, tack coat, delivery, compaction loss, grading or labour. Real surfaces have crowns, slopes and thickness variation, so treat the result as a planning figure and confirm the final order with your asphalt supplier or contractor before paving.
Frequently asked questions
How much asphalt do I need for a driveway?+
Multiply length × width × depth (in feet) to get cubic feet, multiply by the density (about 145 lb/ft³ for hot-mix asphalt), then divide by 2,000 to get tons. A 50 ft × 10 ft driveway at 3 inches needs about 9.06 tons. The calculator does this automatically.
What is the density of asphalt?+
Compacted hot-mix asphalt weighs roughly 145 lb per cubic foot (about 2,322 kg/m³, or 2.3 tonnes per cubic metre). The exact figure varies by mix and aggregate, so your supplier's number is best — enter it in the density box to override the default.
How thick should an asphalt driveway be?+
A residential driveway is usually 2–3 inches of compacted asphalt over a 4–8 inch compacted gravel base. Heavier-use surfaces such as commercial lots and roads use 3–4 inches of asphalt, often in two lifts.
How many tons of asphalt are in a square foot?+
At 3 inches deep and 145 lb/ft³, one square foot needs about 0.018 tons, so roughly 55 sq ft per ton. At 2 inches you get about 83 sq ft per ton, and at 4 inches about 41 sq ft per ton.
How do I convert cubic yards of asphalt to tons?+
One cubic yard equals 27 cubic feet, so at 145 lb/ft³ a cubic yard weighs about 3,915 lb — roughly 1.96 tons. Multiply your cubic yards by about 1.95–2.0 to estimate tons of hot-mix asphalt.
Does the calculator include the gravel base?+
No. This tool estimates only the asphalt (blacktop) layer. The compacted aggregate sub-base beneath it is a separate material with its own depth and density — calculate it with a gravel calculator.
How much extra asphalt should I order for compaction?+
Order about 5–10% extra. Loose hot-mix compacts down when rolled, and you lose some material to edges, waste and an uneven sub-base, so the in-place tonnage is slightly more than the raw geometry suggests.
How is the cost of asphalt estimated?+
Enter your supplier's price per ton and the calculator multiplies it by the tonnage. For example, 9.06 tons at $120/ton is about $1,088 for material. This excludes delivery, base prep, grading and labour.