Quick Reference Guide
Length:
- 1 foot = 0.3048 meters = 12 inches
- 1 inch = 2.54 centimeters = 25.4 mm
- 1 yard = 0.9144 meters = 3 feet
Area & Volume:
- 1 sq ft = 0.0929 sq meters
- 1 cubic yard = 0.765 cubic meters
- 1 acre = 4,047 sq meters = 43,560 sq ft
Essential Construction Conversions
Length & Distance
- Feet → Meters
1 ft = 0.3048 m
- Inches → Centimeters
1 in = 2.54 cm
- Yards → Meters
1 yd = 0.9144 m
- Miles → Kilometers
1 mi = 1.609 km
- Millimeters → Inches
25.4 mm = 1 in
Area Measurements
- Square Feet → Square Meters
1 ft² = 0.0929 m²
- Square Yards → Square Meters
1 yd² = 0.836 m²
- Acres → Hectares
1 acre = 0.405 ha
- Square Inches → Square Centimeters
1 in² = 6.45 cm²
Volume & Capacity
- Cubic Yards → Cubic Meters
1 yd³ = 0.765 m³
- Cubic Feet → Cubic Meters
1 ft³ = 0.0283 m³
- Gallons → Liters
1 gal = 3.785 L
- Board Feet → Cubic Feet
1 BF = 1/12 ft³
Concrete Volume Calculator Reference
| Project Type | Dimensions | Cubic Yards | Cubic Meters | 80lb Bags |
|---|---|---|---|---|
| Concrete Slab (4" thick) | 100 sq ft | 1.23 yd³ | 0.94 m³ | ~41 bags |
| Concrete Footings (12" × 12") | 10 linear ft | 0.37 yd³ | 0.28 m³ | ~12 bags |
| Driveway (10 × 20 ft, 4") | 200 sq ft | 2.47 yd³ | 1.89 m³ | ~82 bags |
Note: Concrete calculations assume standard mix. Always consult with your supplier for accurate quantities.
Lumber Nominal vs. Actual Sizes
| Nominal Size | Actual Size (inches) | Metric Size (mm) | Common Use |
|---|---|---|---|
| 2 × 4 | 1.5" × 3.5" | 38mm × 89mm | Framing, studs |
| 2 × 6 | 1.5" × 5.5" | 38mm × 140mm | Joists, rafters |
| 2 × 8 | 1.5" × 7.25" | 38mm × 184mm | Floor joists, beams |
| 2 × 10 | 1.5" × 9.25" | 38mm × 235mm | Headers, beams |
| 2 × 12 | 1.5" × 11.25" | 38mm × 286mm | Large beams, headers |
| 4 × 4 | 3.5" × 3.5" | 89mm × 89mm | Posts, columns |
| 4 × 6 | 3.5" × 5.5" | 89mm × 140mm | Beams, posts |
| 1 × 6 | 0.75" × 5.5" | 19mm × 140mm | Trim, siding |
Important: Lumber is sold by nominal size but the actual dimensions are smaller due to planing and drying. Always use actual dimensions for structural calculations.
Pressure Conversions (PSI, Bar, kPa)
| PSI | Bar | kPa | Application |
|---|---|---|---|
| 10 PSI | 0.69 bar | 69 kPa | Low-pressure systems |
| 50 PSI | 3.45 bar | 345 kPa | Residential water pressure |
| 100 PSI | 6.89 bar | 689 kPa | High-pressure water |
| 3000 PSI | 207 bar | 20,684 kPa | Concrete strength (standard) |
| 4000 PSI | 276 bar | 27,579 kPa | High-strength concrete |
Professional Tips
Always Add 10% Waste Factor
When ordering materials, always add 10-15% for waste, cuts, and mistakes. This is especially important for concrete, lumber, and flooring.
Understand Nominal vs. Actual Sizes
Lumber "2×4" is actually 1.5" × 3.5". Always use actual dimensions for calculations, especially for structural engineering.
Use Metric for International Projects
International building codes often use metric. Convert and round to standard metric sizes (not direct conversions) for compatibility.
Double-Check Concrete Orders
Concrete is ordered in cubic yards (US) or cubic meters (international). Running short mid-pour is costly. Always round up.
PSI vs. MPa for Concrete
US uses PSI (pounds per square inch), while international uses MPa (megapascals). 3000 PSI ≈ 20 MPa. Know your specs.
Common Questions
How many cubic yards of concrete do I need?
Calculate the volume in cubic feet: Length × Width × Depth (in feet), then divide by 27 to get cubic yards. For example, a 10ft × 10ft × 4in (0.33ft) slab = 33 cubic feet ÷ 27 =1.22 cubic yards. Always add 10% for waste.
What is the difference between board feet and cubic feet?
A board foot is 1 foot × 1 foot × 1 inch (144 cubic inches or 1/12 cubic foot). It's used for lumber pricing. Cubic feet is standard volume measurement. To convert: Board Feet ÷ 12 = Cubic Feet.
How do I convert square feet to square meters?
Multiply square feet by 0.092903. For example, 1,000 sq ft × 0.092903 = 92.9 square meters. Use our square feet to square meters converter for instant calculations.