Construction Industry Unit Conversions: Feet, Inches, Millimeters, and Meters

The construction industry is uniquely split between measurement systems. While many countries use metric, the US construction industry predominantly uses imperial. Even in metric countries, some imperial sizes persist — a 4×8 ft plywood sheet is universal.

Key Construction Units

Imperial: Inch (25.4 mm), Foot (304.8 mm), Yard (0.9144 m), Mile (1.609 km)

Metric: Millimeter, Centimeter, Meter, Kilometer

Lumber Sizing — A Common Confusion

A "2×4" is NOT actually 2" × 4"! This is one of the most confusing aspects of construction.

US standard sheets: 4×8 ft (1219 × 2438 mm). European: 1250 × 2500 mm — close but NOT interchangeable.

Fasteners

Screws: US uses #6, #8, #10, 1/4". Metric uses M3, M4, M5, M6. Approximate equivalents: #8 ≈ M4, #10 ≈ M5.

Conversion Formulas

Feet-Inches to Decimal Feet: 5 ft 6 in = 5 + 6/12 = 5.5 ft

Feet-Inches to Meters: Convert to inches × 0.0254. 5 ft 6 in = 66 × 0.0254 = 1.6764 m

ft² to m²: × 0.092903

cubic yards to m³: × 0.7646

Practical Examples

A 12 ft × 14 ft bedroom = 168 ft² = 15.61 m². Concrete volume: a 10×10 ft slab, 4 inches thick = 1.23 cubic yards.

Use our Feet to Meters Converter and Inches to mm Converter for construction conversions.