Home project calculators that actually help
Calculate materials, quantities, costs, energy use, plumbing, electrical, towing and outdoor projects in seconds. Every formula and assumption is shown, and results are rounded only for display.
20 × 12 ft slab · 4 in thick · 10% waste
Concrete to order
3.26 cu yd
88 cu ft · or 147 bags (80 lb)
Open this in the slab calculator
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Home Energy Calculators
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Guides
- How Much Concrete Do I Need?Measure a slab, convert to cubic yards, decide between bags and ready-mix, and choose a waste allowance.
- How Many Gallons of Paint Do I Need?Measure walls, subtract doors and windows, and account for coats and real-world coverage.
- How Much Does It Cost to Charge an EV at Home?The formula for home charging cost, why charging losses matter, and how to compare with gasoline.
- How Do I Calculate Voltage Drop?The voltage drop formula for copper and aluminum wire, the 3% recommendation, and why ampacity is a separate check.
- How Much Mulch Do I Need?Convert bed area and depth to cubic yards or bags, and decide how deep to spread mulch.