Millibars to PSI Converter
Enter the pressure in millibars below to convert it to psi.
Convert Millibars to PSI
Enter a value in millibars (mbar) to convert to psi (psi).
Millibar to Pounds per Square Inch Conversion Table
Table showing various millibar measurements converted to psi. Click any preset value or arrow to load it into the converter.
| Millibars (mbar) | PSI (psi) |
|---|---|
| 1 mbar | 0.0145038 psi |
| 2 mbar | 0.0290075 psi |
| 2.5 mbar | 0.0362594 psi |
| 5 mbar | 0.0725189 psi |
| 10 mbar | 0.1450377 psi |
| 15 mbar | 0.2175566 psi |
| 20 mbar | 0.2900755 psi |
| 25 mbar | 0.3625943 psi |
| 30 mbar | 0.4351132 psi |
| 50 mbar | 0.7251887 psi |
How to Convert Millibars to PSI
To convert millibars to psi, multiply the pressure by the following conversion ratio: 0.0145038 psi/millibar.
Since one millibar is equal to 0.0145038 psi, you can use this simple formula to convert:
The pressure in psi is equal to the pressure in millibars multiplied by 0.0145038.
For example, here's how to convert 5 millibars to psi using the formula above.
How Many PSI Are in a Millibar?
There are 0.0145038 psi in a millibar, which is why we use this value in the formula above.
Our millibar to pounds per square inch calculator automatically converts your pressure measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.
Millibars and psi are both units used to measure pressure. Keep reading to learn more about each unit.
What Is a Millibar?
A millibar is a unit of pressure equal to 100 pascals (Pa), the base unit for pressure. Meteorological pressure unit equal to 1/1000 of a bar (100 Pa = 1 hPa). [1]
The millibar is classified as a metric and SI-compatible unit of pressure. Millibars can be abbreviated as mbar; for example, 1 millibar can be written as 1 mbar.
In the metric system, "milli" is the standard SI prefix for thousandths, or 10⁻³. This makes the millibar (mbar) a convenient decimal multiple of the bar (100,000 Pa).
In practice, millibars (mbar) are widely used across standard pressure applications within SI metric workflows, engineering documentation, and technical data sheets.
What Is a Pounds per Square Inch?
A pounds per square inch is a unit of pressure equal to 6,894.7572932 pascals (Pa), the base unit for pressure. Imperial & US pressure unit equal to 1 pound-force per square inch (6.89476 kPa). [2]
The pounds per square inch is classified as a US customary and imperial unit of pressure. PSI can be abbreviated as psi; for example, 1 pounds per square inch can be written as 1 psi.
When working with psi (psi) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.
In practice, psi (psi) are widely used across large-scale industrial, bulk, and macro-level pressure specifications within US customary and imperial workflows, engineering documentation, and technical data sheets.
When converting pressure between millibars (mbar) and psi (psi), keep full floating-point precision (1 mbar = 0.0145038 psi; 1 psi = 68.9475729 mbar) during intermediate calculations and round only the final pounds per square inch figure to match your instrument tolerance.
More Millibar & Pounds per Square Inch Conversions
Need to calculate in the opposite direction? Use our psi to millibars calculator to switch your starting unit immediately. You can also explore related tools such as converting psi to millibars, converting bars to psi, or converting kilopascals to psi.
Frequently Asked Questions
References
- [1]NIST SP 811 StandardNIST SP 811 (NIST SP 811 App. B.9 (Pressure & Stress))·Pressure Metrology Standard — Millibars (mbar) to PSI (psi)
- [2]NIST CUU SpecificationNIST CUU (Derived SI Unit: Pascal (Pa))·Unit Specifications: Millibar (mbar) & Pounds per Square Inch (psi)
- [3]BIPM ReferenceBIPM (SI Brochure (9th Ed.) — Mechanics)·Conversion Factors & Mathematical Basis (mbar to psi)