Engineering unit converter
Enter your values. The answer and the full worked solution update as you type.
Result
| Unit | Value |
|---|---|
| pascal (Pa) | 689475.729 Pa |
| kilopascal (kPa) | 689.4757 kPa |
| megapascal or N/mm² (MPa) | 0.6894757 MPa |
| gigapascal (GPa) | 0.0006894757 GPa |
| bar | 6.894757 bar |
| millibar or hectopascal (mbar) | 6894.757 mbar |
| standard atmosphere (atm) | 6.804596 atm |
| pound-force per square inch (psi) | 100 psi |
| kilopound per square inch (ksi) | 0.1 ksi |
| pound-force per square foot (psf) | 14400 psf |
| torr (Torr) | 5171.493 Torr |
| millimetre of mercury (mmHg) | 5171.493 mmHg |
| inch of mercury (inHg) | 203.602 inHg |
| millimetre of water (mmH₂O) | 70306.958 mmH₂O |
| inch of water (inH₂O) | 2767.99 inH₂O |
Convert between SI and US customary units for the quantities engineers use most: length, area, volume, mass, force, pressure and stress, energy, power, temperature, volumetric flow rate, speed, torque and density. The calculator shows the conversion through the SI unit, the conversion factor in both directions and a table with the value in every unit of the quantity. The factors follow the exact definitions, such as 1 in = 25.4 mm and 1 lb = 0.45359237 kg.
Step-by-step solution
Convert to the SI unit
Convert from the SI unit
Conversion factor
Key formulas
- Conversion
- new value = value × size of the old unit / size of the new unit
- Temperature
- °F = °C × 9/5 + 32, K = °C + 273.15
- Common factors
- 1 in = 25.4 mm, 1 lb = 0.4536 kg, 1 lbf = 4.448 N, 1 psi = 6.895 kPa, 1 kWh = 3.6 MJ
How to convert units
- Write the value with its unit and look up the factor that relates the unit to the SI unit, for example 1 psi = 6894.757 Pa.
- Multiply by that factor to get the value in the SI unit: 100 psi × 6894.757 Pa/psi = 689 476 Pa.
- Divide by the factor of the target unit: 689 476 Pa ÷ 100 000 Pa/bar = 6.895 bar.
- Check the units cancel like fractions: psi × (Pa/psi) × (bar/Pa) = bar.
- Temperatures are different: convert through kelvin with a formula, because the scales have different zero points.
Questions and answers
Which conversions are exact?
Most engineering units are defined exactly in SI units: 1 in = 0.0254 m, 1 lb = 0.45359237 kg, 1 lbf = 4.4482216152605 N, 1 US gallon = 231 in³, 1 atm = 101 325 Pa and 1 cal = 4.184 J. Units based on a column of mercury or water, such as inHg and inH₂O, use conventional values.
What is the difference between lb and lbf?
The pound (lb) is a unit of mass, 0.4536 kg. The pound-force (lbf) is the weight of one pound under standard gravity, 4.448 N. In US engineering the slug, 32.17 lb, is the mass that accelerates at 1 ft/s² under 1 lbf.
How do I convert °C to °F?
Multiply by 9/5 and add 32: 100 °C = 212 °F. Back from °F: subtract 32 and multiply by 5/9. A temperature difference of 1 °C is 1.8 °F, without the 32.
Which calorie is used?
The thermochemical calorie, 4.184 J; the food Calorie is a kilocalorie, 4184 J. The International Table calorie (4.1868 J), used in steam tables, differs by about 0.07%.
Which horsepower is used?
Mechanical horsepower, 550 ft·lbf/s = 745.7 W. Metric horsepower (PS), common in Europe for car engines, is 735.5 W and is listed separately.
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