How much asphalt do I need? The formula
Asphalt is sold by the ton, but you measure your driveway by area and depth — so the whole job of an asphalt calculator is converting volume to weight with the mix density.
ft³ = areaft² × (depthin ÷ 12)
tons = ft³ × densitylb/ft³ ÷ 2000
cubic yards = ft³ ÷ 27 · tonnes = tons × 0.90718
Hot-mix asphalt compacted in place generally runs 140–155 lb/ft³, with 145 the common planning figure — that makes a cubic yard about 3,915 lb, or roughly 1.96 tons per cubic yard. A 40×12 ft driveway at 3″ is 120 ft³, about 8.7 tons before waste. Enter your numbers above and the calculator shows tons, tonnes, cubic yards and cubic feet together.
How do you convert square yards of asphalt to tons?
Multiply the square yards by 9 to get square feet, by the depth in feet to get cubic feet, then by the density and divide by 2,000. At the typical 145 lb/ft³, that works out to about 0.054 tons per square yard per inch of depth — the familiar contractor rule of roughly 110 lb per square yard per inch.
tons = yd² × 9 × (depthin ÷ 12) × density ÷ 2000
at 145 lb/ft³: tons ≈ yd² × depthin × 0.0544
Worked example: 100 square yards at 3″ deep is 100 × 9 × 0.25 = 225 ft³; at 145 lb/ft³ that’s 32,625 lb, or about 16.3 tons. Going the other way, one ton at 3″ covers about 6.1 square yards (55 ft²). The quick converter in the calculator runs this in both directions — type square yards to get tons, or tons to get square yards — at whatever depth and density you set.
Tons per area at common depths
All figures below are computed from the density formula at 145 lb/ft³; change the density above and the live results adjust, even if this reference table doesn’t.
| Compacted depth | lb per yd² | Tons per 100 ft² | ft² per ton | yd² per ton |
|---|---|---|---|---|
| 2″ | 217.5 | 1.21 | 82.8 | 9.2 |
| 3″ | 326.3 | 1.81 | 55.2 | 6.1 |
| 4″ | 435.0 | 2.42 | 41.4 | 4.6 |
How thick should an asphalt driveway be?
Residential driveways are commonly paved at 2–3″ compacted over 4–8″ of compacted crushed-stone base, with thicker sections (3–4″) where heavier vehicles park. The base does most of the structural work, so a thin lift over a good base outlasts a thick lift over a poor one. These are general ranges — soil, climate and traffic all move the answer, and your paving contractor or local requirements take precedence. Figure the base layer itself with the gravel calculator.
Overlay: resurfacing over existing asphalt
An overlay is a thinner lift — commonly 1.5–2″ — paved on top of an existing surface that’s been cleaned, repaired and tack-coated. The math is identical, just with less depth: switch to the overlay tab and the depth default drops accordingly. If the old surface is badly cracked, milling it off and repaving may serve better than overlaying, which is where the millings mode comes in for the recycled material.
Asphalt millings (recycled asphalt)
Millings — the ground-up material from milled pavement, also called RAP — are looser and lighter than fresh hot mix, typically around 110–120 lb/ft³. The millings tab loads a 115 lb/ft³ default you can edit. Millings compact significantly after placement, so a 15% allowance in the waste field is a reasonable starting point for a driveway you’ll roll or drive in.
Cold patch by the bag
For pothole and edge repair, cold patch comes in bags rather than by the ton. Switch to the cold patch tab, enter the repair area and depth, and the bag yield from your product’s label (a 50 lb bag is commonly around 0.4–0.5 ft³) — the calculator divides the volume by the yield and rounds up to whole bags.
Estimating asphalt cost with your local price per ton
Asphalt prices move with oil prices and vary a lot by region and load size, so this calculator deliberately ships with no built-in price. Get a per-ton quote from your local plant or paving contractor, enter it in the price field, and the cost line multiplies it by the tonnage including waste. For a full driveway estimate, remember the asphalt is only part of the picture — excavation, base stone (see the gravel calculator) and labor usually dominate the bill.