Common engineering conversions
| From | To | Multiply by |
|---|---|---|
| psi | kPa | 6.894757 |
| bar | psi | 14.5038 |
| in H₂O | psi | 0.036127 |
| ft of water | psi | 0.4335 |
| ft·lbf | N·m | 1.355818 |
| in·lbf | N·m | 0.112985 |
| lbf | N | 4.448222 |
| hp | kW | 0.745700 |
| ton of refrigeration | BTU/h | 12,000 |
| gpm | L/min | 3.785412 |
| cfm | m³/h | 1.699011 |
Temperature
°C = (°F − 32) × 5 ÷ 9
°F = °C × 9 ÷ 5 + 32
K = °C + 273.15
°R = °F + 459.67
Temperature differences convert differently from temperatures: a change of 1 °C equals a change of 1.8 °F.
Notes on the units
- Inches of water uses water at 39.2 °F (4 °C). HVAC gauges calibrated at 60 °F read about 0.1% differently.
- Horsepower is mechanical horsepower (550 ft·lbf/s), the rating used on US motors. Metric horsepower (PS) is 1.4% smaller.
- Gallons are US gallons (231 in³). An imperial gallon is 20% larger.
Frequently asked questions
- How do I convert psi to feet of head?
- Multiply psi by 2.307 for water. 50 psi is about 115 ft of head.
- How many ft-lbs is 100 N·m?
- 100 ÷ 1.3558 = 73.8 ft·lbf.
Quick answers
- PSI to kPa
- ft-lb to N·m
- Fahrenheit to Celsius
- Horsepower to kW
- Bar to PSI
- N·m to ft-lb
- Celsius to Fahrenheit
Results are estimates for planning and education. Verify against the current code edition your jurisdiction has adopted, manufacturer data and a licensed professional before you build or install.