Standard Atmosphere
The standard atmosphere (atm) is a unit of pressure defined as exactly 101,325 Pascals. It represents the average atmospheric pressure at sea level on Earth and is used as a fundamental reference in chemistry and physics.
Conversion Values (per 1 atm)
Base Reference Unit| Unit Name | Symbol | Equivalent Value | System |
|---|---|---|---|
| Standard Atmosphere | atm | 1 | Base |
| Bar | bar | 1.01325 | Metric |
| Pascal | Pa | 101,325 | SI |
| Pound-force per sq inch | psi | 14.6959 | Imperial |
| Millimeters of Mercury | mmHg | 760 | Metric |
Bar
The bar is a metric unit of pressure defined as exactly 100,000 Pascals. Because it is very close to the atmospheric pressure at sea level, it is widely used in meteorology and engineering.
Conversion Values (per 1 bar)
Metric Pressure Unit| Unit Name | Symbol | Equivalent Value | System |
|---|---|---|---|
| Standard Atmosphere | atm | 0.986923 | Base |
| Bar | bar | 1 | Metric |
| Pascal | Pa | 100,000 | SI |
| Pound-force per sq inch | psi | 14.5038 | Imperial |
| Millimeters of Mercury | mmHg | 750.062 | Metric |
Pascal
The Pascal (Pa) is the SI derived unit of pressure, defined as one newton per square meter (1 N/m²). It is the standard in scientific research and materials science.
Conversion Values (per 1 Pa)
SI Derived Unit| Unit Name | Symbol | Equivalent Value | System |
|---|---|---|---|
| Standard Atmosphere | atm | 9.8692 × 10⁻⁶ | Base |
| Bar | bar | 1 × 10⁻⁵ | Metric |
| Pascal | Pa | 1 | SI |
| Pound-force per sq inch | psi | 1.45038 × 10⁻⁴ | Imperial |
| Millimeters of Mercury | mmHg | 0.00750062 | Metric |
Pound-force per Square Inch
PSI is a unit of pressure resulting from a force of one pound-force applied to an area of one square inch. It is widely used in the US for automotive, hydraulic systems, and industrial applications.
Conversion Values (per 1 psi)
Imperial Pressure Unit| Unit Name | Symbol | Equivalent Value | System |
|---|---|---|---|
| Standard Atmosphere | atm | 0.068046 | Base |
| Bar | bar | 0.0689476 | Metric |
| Pascal | Pa | 6,894.76 | SI |
| Pound-force per sq inch | psi | 1 | Imperial |
| Millimeters of Mercury | mmHg | 51.7149 | Metric |
Millimeters of Mercury
mmHg is a manometric unit of pressure, formerly defined as the extra pressure generated by a column of mercury one millimeter high. Today, it is primarily used in medicine (blood pressure) and physiology.
Conversion Values (per 1 mmHg)
Manometric Unit| Unit Name | Symbol | Equivalent Value | System |
|---|---|---|---|
| Standard Atmosphere | atm | 0.00131579 | Base |
| Bar | bar | 0.00133322 | Metric |
| Pascal | Pa | 133.322 | SI |
| Pound-force per sq inch | psi | 0.0193368 | Imperial |
| Millimeters of Mercury | mmHg | 1 | Metric |