Pressure Converter
Convert between pascals, kilopascals, bar, psi, atmospheres and millimetres of mercury.
Formula and sources updated · Data sources · 1View algorithm, constants and default inputs (JSON)
1 psi ≈ 0.0689475729 bar
About this calculator
Pressure units come from several traditions: pascals from the SI system, psi from imperial engineering, bar from meteorology and mmHg from medicine. They all convert through pascals.
Worked example
calculated with the default values below
Value 1 · From Bar · To PSI · Decimal places 4 Result 14.5038 · PSI 14.5038 psi · Bar 1.000000 bar · Kilopascals 100.0000 kPa
Method and assumptions
Formula basis and scope
Convert pressure via pascals; pressure is force per area.
Only the displayed unit definitions are converted; rounding and measurement uncertainty are separate.
Data sources
Disclaimer
These calculators give general conversion results. Rounding and the precision of the value you enter both affect the output, so treat displayed decimals as indicative rather than exact.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
P_out = P_in × k_from ÷ k_to
- P_in
- Input pressure
- k_from
- Factor of input unit (per Pa)
- k_to
- Factor of target unit (per Pa)
- P_out
- Converted pressure
Lookup factors in pascals: Pa = 1, kPa = 1000, MPa = 10⁶, bar = 100000, mbar = 100, psi = 6894.757293168, atm = 101325, mmHg = 133.322387415, inHg = 3386.389, kg/cm² = 98066.5.
Frequently asked questions
Why does one bar convert to almost exactly 14.5 psi rather than 15?
The bar is defined as exactly 100,000 pascals, while psi is one pound-force per square inch, equal to 6,894.757 pascals. Dividing 100,000 by 6,894.757 gives 14.504 psi, so one bar is always 14.50 psi, never a round 15. The converter applies this fixed pascal bridge for every unit pair, including mmHg and inHg used in medicine.