Pressure Unit Conversion
Quick answer: 1 bar = 100,000 Pa = 100 kPa ≈ 14.504 psi, 1 MPa = 1 N/mm² = 10 bar, 1 atm = 101,325 Pa, 1 kgf/cm² = 0.980665 bar and 1 mmHg ≈ 133.32 Pa.
Pascal, kPa, MPa, N/mm², bar, atmosphere, kgf/cm², psi, mmHg and water column – enter a value and see every conversion.
How the calculation works
Enter a pressure or stress and choose the starting unit (for example bar, MPa or psi). The table shows the same pressure in pascals, kilopascals, megapascals, N/mm², bar, atmospheres, kgf/cm², psi and ksi, millimetres of mercury and metres of water column.
Formula and assumptions
The base unit is the pascal (1 Pa = 1 N/m²). 1 MPa = 1 N/mm² = 1,000,000 Pa and 1 bar = 100,000 Pa. Gravitational units use g₀ = 9.80665 m/s²: 1 kgf/cm² = 98,066.5 Pa, 1 mH₂O = 9,806.65 Pa. 1 psi = 1 lbf/in² = 6,894.757 Pa; 1 mmHg (conventional) = 133.322387415 Pa.
More worked examples
- C30/37 concrete: compressive strength 30 MPa = 30 N/mm² = 300 bar.
- Plumbing pressure of 2.5 bar: 2.5 × 14.504 ≈ 36.3 psi.
- Tyres at 32 psi in bar: 32 × 0.0689476 ≈ 2.21 bar.
- Hydrostatic pressure of 10 m of water: 10 × 9,806.65 Pa ≈ 0.98 bar.
Units of pressure
| Unit | in Pa | Other |
|---|---|---|
| 1 Pa | 1 | 1 N/m² |
| 1 kPa | 1,000 | 0.01 bar |
| 1 bar | 100,000 | 14.5038 psi |
| 1 MPa (N/mm²) | 1,000,000 | 10 bar |
| 1 atm | 101,325 | 1.01325 bar |
| 1 kgf/cm² (at) | 98,066.5 | 0.980665 bar |
| 1 psi | 6,894.76 | 0.0689 bar |
| 1 mmHg | 133.322 | ≈ 1 Torr |
Common mistakes
- Confusing MPa and bar: 1 MPa is 10 bar, not 1 bar.
- Treating the atmosphere (101,325 Pa) and the bar (100,000 Pa) as equal – they differ by 1.3 %.
- Mixing gauge pressure (psig, bar g) and absolute pressure.
Frequently asked questions
How many psi is 1 bar?
1 bar ≈ 14.504 psi. Conversely 1 psi ≈ 0.0689 bar, so 30 psi is about 2.07 bar.
Is MPa the same as N/mm²?
Yes, 1 MPa = 1 N/mm². That is why the strength of concrete and steel can be given in either unit.
What is the difference between bar and atmosphere?
The standard atmosphere is 101,325 Pa, the bar 100,000 Pa. The technical atmosphere (kgf/cm²) is 98,066.5 Pa.
How many bar is 1 metre of water column?
1 mH₂O = 9,806.65 Pa ≈ 0.098 bar. Ten metres of water give roughly 1 bar of pressure.
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Calculations use common consumption rates and manufacturers' technical data sheets; results are estimates. Methodology · Standards · About