Asphalt tonnage is how much hot mix a paving job needs by weight, in short tons of 2,000 pounds, which is how the plant sells it and how most paving gets priced.
The formula:
tons = area (sq ft) × depth (in) ÷ 12 × unit weight (lb per cu ft) ÷ 2,000
Dividing by 12 turns inches into feet. For 10,000 square feet at 2 inches, that's 10,000 × 2 ÷ 12 = 1,667 cubic feet. At 145 pounds per cubic foot, that's 241,667 pounds, or about 121 tons.
A shortcut worth remembering: at 145 pounds, every inch of depth over 1,000 square feet is about 6 tons. So an extra half inch across a 10,000 square foot lot is about 30 tons.
145 is a common default, not your number. The mix design from your plant lists the compacted unit weight, and it usually lands somewhere around 140 to 150. Use the real one.
The formula gives you the tons for a perfectly flat surface at exactly the specified depth. Real lots aren't, so add a waste factor for the surface you're paving over. Figure binder and surface courses separately, because they're different mixes at different prices. The asphalt tonnage calculator does the arithmetic.