US Construction Unit Conversion Chart
A practical construction conversion reference for inches, feet, square feet, cubic yards, US gallons, pounds, PSI and common metric units.
Multiply inches by 25.4 for millimeters, feet by 0.3048 for meters, square feet by 0.09290304 for square meters, and cubic yards by about 0.764555 for cubic meters. Select the type of quantity before converting: a length factor cannot convert area or volume.
Use this chart for a quick check, or open the US construction unit converter to convert a numeric value between the listed categories. Rounded factors below are estimating references; retain the precision required by the project.
Quick length conversions
| From | To | Factor |
|---|---|---|
| inches | millimeters | × 25.4 |
| feet | meters | × 0.3048 |
| yards | meters | × 0.9144 |
| miles | kilometers | × 1.609344 |
The international foot is exactly 0.3048 meter. For routine building dimensions, that is the foot used in the conversion. Historical survey records may require different treatment.
Area conversions
| From | To | Factor |
|---|---|---|
| square feet | square meters | × 0.09290304 |
| square yards | square meters | × 0.83612736 |
| acres | square feet | × 43,560 |
Do not multiply square feet by 0.3048. That is a length factor. Area factors are squared because both dimensions are converted.
Volume conversions
| From | To | Factor |
|---|---|---|
| cubic feet | cubic meters | × 0.0283168 |
| cubic yards | cubic feet | × 27 |
| cubic yards | cubic meters | × 0.764555 |
| US gallons | liters | × 3.78541 |
US liquid gallons and UK imperial gallons are different. A supplier specification that says only “gallons” needs context before conversion.
Weight and pressure
| From | To | Factor |
|---|---|---|
| pounds | kilograms | × 0.453592 |
| US short tons | pounds | × 2,000 |
| PSI | kilopascals | × 6.89476 |
Check whether “ton” means a US short ton, metric tonne or UK long ton. They are not interchangeable.
Worked examples from a takeoff
Drawing dimension: A 12 ft 6 in opening is 12.5 ft, so 12.5 × 0.3048 = 3.81 m. Convert the inches first using the feet-and-inches method.
Floor area: 250 sq ft × 0.09290304 = 23.22576 m², displayed as 23.23 m². Do not use the length factor: 250 × 0.3048 is not an area conversion. For an unmeasured room, first calculate its square footage.
Concrete volume: 3.5 yd³ × 0.764555 ≈ 2.67594 m³, or about 2.68 m³. Converting units does not add a waste allowance; keep any allowance already included with the original quantity.
Liquid volume: 5 US gal × 3.78541 ≈ 18.92705 L, or about 18.93 L. Choose Gallons (US) in the converter. Imperial gallons produce a different answer.
Temperature: Fahrenheit uses an offset as well as a multiplier: °C = (°F − 32) × 5 ÷ 9. For 77°F, (77 − 32) × 5 ÷ 9 = 25°C. Do not use this formula for a temperature difference without removing the offset.
A safe conversion workflow
- Identify the kind of quantity: length, area, volume, weight, temperature or pressure.
- Record the source unit exactly.
- Use enough precision for the purpose.
- Convert once from the original value.
- Round only the displayed or ordering result.
- Keep the original value beside the conversion so somebody else can check it.
Open the US construction unit converter for length, area, volume, weight, temperature, pressure and speed conversions.
The factors above align with NIST’s approximate US customary-to-metric reference and Guide to the SI conversion factors. For fabrication, surveying, engineering or code work, use the precision and source required by the project—not a rounded pocket reference.
Use the related US tools
Check the next part of your estimate
Feet and Inches to Decimal Feet: Formula and Examples
Convert 8 ft 6 in to 8.5 feet, handle fractional inches, and convert decimal feet back to feet and inches without confusing inches with decimals.
How to Calculate Square Footage: Rooms, Walls and Cutouts
Calculate square feet from feet and inches, work through an L-shaped room, subtract openings, and turn measured area into a material order.
How to Calculate Concrete in Cubic Yards
Calculate slab concrete from feet and inches, convert cubic feet to yards, and check a 20-by-12-foot example with the allowance shown separately.