Methodology & sources
Each calculator on Paving Calculators uses a published, industry-standard formula. Below is the exact method behind every tool. Constants such as material densities follow common supplier and engineering references; local prices are user-entered so the estimate reflects your market.
| Tool | Formula |
|---|---|
| Concrete Slab Cost Calculator | Cubic yards = (Length ft × Width ft × Thickness in ÷ 12) × (1 + waste%) ÷ 27. Ready-mix is priced per cubic yard; bagged mix yields ≈0.45 cu ft (60 lb) or ≈0.60 cu ft (80 lb). |
| French Drain Cost Calculator | Gravel cu yd = (Length × Width in ÷ 12 × Depth in ÷ 12 × 0.85) ÷ 27. Tons ≈ yd³ × 1.4. Pipe ≈ length × 1.05. Cost = gravel tons × price + pipe ft × price. |
| Deck Stain Calculator | Gallons = (Length × Width × railings-factor × Coats) ÷ Coverage per gallon. Most deck stains cover 150–350 sq ft per gallon; rough or thirsty wood is at the lower end. |
| Asphalt Driveway Cost Calculator | Tons = (Length × Width × Thickness in ÷ 12 × 145 ÷ 2000) × (1 + waste%). Installed cost = tons × price per ton + area × labour per sq ft. |
| Gravel Calculator | Cubic yards = (Length × Width × Depth in ÷ 12) ÷ 27. Tons ≈ cubic yards × 1.4. Cost = tons × price per ton. |
Estimates exclude labour, delivery, tax and site-specific conditions unless stated. Always confirm with your supplier.