Sq Ft to Cubic Feet Calculator
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How to Convert Square Feet to Cubic Feet
Square feet measures area — a flat, two-dimensional surface. Cubic feet measures volume — a three-dimensional space. To calculate volume, you need to add a third dimension: depth, height, or thickness. Pouring a slab? The concrete calculator handles volume directly; estimate spend with the cost per square foot calculator, or measure the surface first with the main square footage calculator.
The Core Formula
Volume Formula
Key FormulaExample: 200 sq ft × 0.5 ft (6 inch slab) = 100 cubic feet
When Depth Is Given in Inches
Divide the depth in inches by 12 to convert to feet before multiplying. A 3-inch deep mulch layer over 500 sq ft: 500 × (3 ÷ 12) = 500 × 0.25 = 125 cubic feet. Our calculator handles this unit conversion automatically.
Converting to Cubic Yards
Divide cubic feet by 27 to get cubic yards (since 1 cubic yard = 3ft × 3ft × 3ft = 27 cubic feet). Concrete and fill dirt are typically sold by the cubic yard. 81 cubic feet ÷ 27 = 3 cubic yards.
Common Depth-to-Volume Reference
| Material | Typical Depth | Per 100 Sq Ft | Per 1,000 Sq Ft |
|---|---|---|---|
| Mulch | 3 inches | 25 cu ft | 250 cu ft |
| Topsoil | 6 inches | 50 cu ft | 500 cu ft |
| Concrete slab | 4 inches | 33.33 cu ft | 333.33 cu ft |
| Gravel base | 4 inches | 33.33 cu ft | 333.33 cu ft |
| Sand fill | 2 inches | 16.67 cu ft | 166.67 cu ft |
| Poured asphalt | 3 inches | 25 cu ft | 250 cu ft |
To convert cubic feet to cubic yards (for ordering), divide by 27. For mulch over 1,000 sq ft at 3 inches: 250 cu ft ÷ 27 = 9.26 cu yd — order 10 cubic yards.
Practical Applications for Volume Calculation
Concrete Slabs & Foundations
Before pouring concrete, calculate the volume in cubic feet, then divide by 27 for cubic yards. Concrete suppliers sell by the cubic yard. A 20 ft × 20 ft patio at 4 inches depth: 400 × 0.333 = 133.33 cubic feet = 4.94 cubic yards. Order 5.5 yards including waste.
Mulch & Landscaping Beds
Garden beds and landscaping areas need mulch at 2–4 inch depths. Calculate the bed area in square feet, choose depth, and find cubic feet. Most bags are 2 cubic feet; bulk orders are by the cubic yard.
Swimming Pool & Water Features
Pool volumes are calculated in cubic feet, then converted to gallons (1 cu ft = 7.48 gallons). A pool 20 ft × 40 ft × 5 ft average depth = 4,000 cu ft = 29,922 gallons to fill.
Fill Dirt & Excavation
When filling low spots or grading land, calculate the volume in cubic feet. Divide by 27 for cubic yards to order the correct number of truckloads (typically 10–14 cu yd per dump truck).
100 Square Feet to Cubic Feet
200 Square Feet to Cubic Feet
300 Square Feet to Cubic Feet
400 Square Feet to Cubic Feet
500 Square Feet to Cubic Feet
1000 Square Feet to Cubic Feet
Square Feet to Cubic Feet by Depth
| Sq Ft | 2" | 3" | 4" | 6" | 12" |
|---|---|---|---|---|---|
| 50 | 8.33 | 12.5 | 16.67 | 25 | 50 |
| 100 | 16.67 | 25 | 33.33 | 50 | 100 |
| 150 | 25 | 37.5 | 50 | 75 | 150 |
| 200 | 33.33 | 50 | 66.67 | 100 | 200 |
| 300 | 50 | 75 | 100 | 150 | 300 |
| 400 | 66.67 | 100 | 133.33 | 200 | 400 |
| 500 | 83.33 | 125 | 166.67 | 250 | 500 |
| 750 | 125 | 187.5 | 250 | 375 | 750 |
| 1,000 | 166.67 | 250 | 333.33 | 500 | 1,000 |
| 2,000 | 333.33 | 500 | 666.67 | 1,000 | 2,000 |
All values in cubic feet. Formula: Sq Ft × (Depth in inches ÷ 12) = Cubic Feet.
Volume Visual Comparison
Bag Calculator
How many bags do you need? Enter your total cubic feet or use the calculator above, then see the bag count below.
Material Estimator
Select a material and enter your area and depth to get a quantity estimate with cost guidance.
Specialized Square Feet Calculators
Each tool is purpose-built with its own dedicated calculator, visual diagrams, and step-by-step guidance.
Triangle
Find the area of any triangle using base × height or Heron's formula with three side lengths.
Irregular Shape
Break any complex shape into rectangles and triangles. Add sections and sum them automatically.
Inches
Enter measurements in inches and get instant square feet results. Includes a quick-reference conversion table.
From Meters
Convert metric measurements to square feet. Perfect for international real estate and imported materials.
Linear Feet
Convert linear footage to square feet for lumber, carpet, fencing, decking, and rolled materials.
Sq Meters
Convert sq ft to sq m with live dual display. Essential for international real estate and architecture.
Sq Yards
Divide sq ft by 9 to get sq yd. Perfect for carpet ordering, sod purchases, and fabric estimates.
Acres
Convert property area from sq ft to acres. Ideal for land sales, farming, zoning, and lot size comparisons.
Cubic Feet
Add depth to any area to calculate volume. Essential for concrete, mulch, soil, gravel, and pool planning.
House
Add rooms one by one and get your home's total square footage, with a live bar chart breakdown per room.
Room
Measure rectangular or L-shaped rooms for flooring, paint, and renovation budgeting with instant cost estimates.
Wall
Get net wall area for paint, wallpaper, or tile by subtracting doors and windows from the gross surface.
Tile
Enter room size and tile dimensions to calculate tile count, boxes to buy, and total material cost including waste.
Concrete
Get slab area, cubic yards of concrete, bags needed, and pour cost for any project.
Land
Measure any property lot or parcel in sq ft and acres. Supports rectangular, triangular, and irregular shapes.
BTU Calculator
Calculate heating and cooling BTU needs per square foot based on climate zone, ceiling height, and insulation.
Cost
Estimate total project cost from area and price per square foot. Compare scenarios with tax and markup.
Flooring
Find exact flooring material for hardwood, laminate, vinyl, or carpet with waste factor and box count.
Roof
Get true roof surface area using pitch multiplier. Includes roofing squares, shingle bundles, and cost.
Paint Area
Get paintable wall area with door and window deductions. Calculates gallons, coats, and total paint cost.
Estimation
Add multiple areas, apply buffer percentages, and get quick estimates for budgeting any project.
People Also Search
100 sq ft to cubic feet
To convert 100 square feet to cubic feet, you need to know the depth or thickness. At 4 inches deep, 100 sq ft equals 33.33 cubic feet (100 × 4/12 = 33.33). At 6 inches, it's 50 cubic feet. At 1 foot deep, 100 sq ft equals exactly 100 cubic feet. This is a common calculation for small concrete pads, garden beds, and patio areas. Use the calculator above to try different depths instantly.
500 sq ft mulch
Covering 500 square feet with mulch depends on the depth you choose. At the recommended 3-inch depth, you'll need 125 cubic feet of mulch (500 × 3/12 = 125). That's about 4.63 cubic yards, or roughly 63 standard 2-cubic-foot bags. At 4 inches deep, you'll need 166.67 cubic feet — about 6.17 cubic yards or 84 bags. Most landscapers recommend 3 inches for weed suppression and moisture retention in garden beds.
10×10 slab cubic feet
A 10×10 foot slab has an area of 100 square feet. The cubic feet depends on thickness: at the standard 4-inch slab thickness, 100 × (4/12) = 33.33 cubic feet, which is 1.23 cubic yards of concrete. For a 6-inch slab (driveways, garages), 100 × 0.5 = 50 cubic feet = 1.85 cubic yards. Always order 10–15% extra concrete for waste and spillage.
12×12 room cubic feet
A 12×12 foot room has 144 square feet of floor area. To find the room's air volume in cubic feet, multiply by the ceiling height. With a standard 8-foot ceiling: 144 × 8 = 1,152 cubic feet. With a 9-foot ceiling: 144 × 9 = 1,296 cubic feet. With a 10-foot ceiling: 144 × 10 = 1,440 cubic feet. This measurement is used for HVAC sizing, air quality calculations, and heating/cooling estimates.
1000 square feet 6 inches
For 1,000 square feet at 6 inches deep, the calculation is straightforward: 1,000 × (6/12) = 1,000 × 0.5 = 500 cubic feet. That equals 18.52 cubic yards. If you're buying bagged material, that's 250 bags (2 cu ft each) or 167 bags (3 cu ft each). For large projects like this, ordering bulk delivery by the cubic yard is far more economical — typically $30–$60 per cubic yard for mulch or topsoil, versus $3–$5 per bag.
Related Calculators
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Frequently Asked Questions
Square feet (ft²) measures 2-dimensional area — the surface of a floor, wall, or plot of land. Cubic feet (ft³) measures 3-dimensional volume — the amount of space inside a container, the depth of fill, or the capacity of a room. Cubic feet = square feet × height/depth.
Since square feet measures area (2D) and cubic feet measures volume (3D), you cannot convert them directly without knowing the depth or height. For example, if the depth is 1 foot, 2 cubic feet covers 2 square feet. If the depth is 2 inches (which is 0.167 feet), 2 cubic feet covers 12 square feet.
Multiply the square footage by the depth or height in feet. If the depth is in inches, divide by 12 first. Example: 300 sq ft × (6 inches ÷ 12) = 300 × 0.5 = 150 cubic feet.
It depends on the depth. At 4 inches deep: 100 × (4/12) = 33.33 cubic feet. At 6 inches: 100 × 0.5 = 50 cubic feet. At 12 inches (1 foot): 100 × 1 = 100 cubic feet. You always need a depth to convert area to volume.
A 10×10 ft slab = 100 sq ft. At 4 inches thick: 100 × (4/12) = 33.33 cubic feet = 1.23 cubic yards. At 6 inches thick: 100 × 0.5 = 50 cubic feet = 1.85 cubic yards. Order at least 10% extra for waste.
At 3 inches deep: 500 × (3/12) = 125 cubic feet = 4.63 cubic yards. That's about 63 bags (2 cu ft each) or 42 bags (3 cu ft each). At 4 inches deep: 500 × (4/12) = 166.67 cubic feet = 6.17 cubic yards. Order 5–7 cubic yards depending on depth.
Exactly 27 cubic feet. Since 1 yard = 3 feet, 1 cubic yard = 3 × 3 × 3 = 27 cubic feet. Always divide cubic feet by 27 when ordering bulk materials sold by the cubic yard.
Divide your total cubic feet by the bag size. Most mulch bags are 2 cu ft or 3 cu ft. For example, 125 cubic feet ÷ 2 = 63 bags (2 cu ft) or 125 ÷ 3 = 42 bags (3 cu ft). Always round up and add 5–10% for waste.
Calculate the volume: area (sq ft) × depth (in feet) = cubic feet. Divide by 27 for cubic yards. A 20×20 ft patio at 4 inches: 400 × 0.333 = 133.33 cu ft = 4.94 cu yd. Order 5.5 yards to account for waste and spillage.
1 cubic foot = 7.48052 US gallons. So 100 cubic feet = 748 gallons, and 1,000 cubic feet = 7,481 gallons. This conversion is essential for pool volume, water tank capacity, and irrigation calculations.
Yes. Measure the room's square footage (length × width), then multiply by the ceiling height in feet. A 12 × 15 ft room with 9 ft ceilings: 180 × 9 = 1,620 cubic feet of air volume. This is used for HVAC sizing and air exchange rate calculations.
For most garden beds, 2–4 inches of mulch is ideal. 2 inches suppresses weeds and retains moisture; 3–4 inches is better for moisture retention in dry climates. Avoid piling mulch against tree trunks (keep it 6 inches away). Calculate: area × depth in feet = cubic feet needed.