BARG to PSI Conversion: What It Means & How to Convert
Barg stands for bar gauge— pressure measured relative to atmospheric pressure. To convert barg to PSI, multiply by 14.5038. For example, 10 barg × 14.5038 = 145 PSIG.
What Does Barg Mean?
A unit of pressure expressed in bar, measured relative to ambient atmospheric pressure (approximately 1.01325 bar or 14.696 PSI at sea level). Barg is the metric equivalent of PSIG (pounds per square inch gauge) and is the standard unit for industrial pressure gauges, hydraulic system specifications, and component ratings in metric-standard environments.
The "g" suffix in barg is critical. It signals that the measurement is gauge pressure — the pressure above and beyond the atmospheric baseline. This is the pressure your gauge reads when connected to a pressurized system. A gauge reading of 0 barg does not mean no pressure exists; it means the system pressure equals atmospheric pressure.
Bar vs. Barg vs. Bara — The Difference Explained
Three closely related terms appear in pressure specifications across industrial, oil & gas, and process engineering documentation. Understanding each prevents specification errors.
| Term | Full Name | Reference Point | At Sea Level | Primary Use |
|---|---|---|---|---|
| bar | Bar (context-dependent) | Context-dependent | Ambiguous — specify gauge or absolute | General metric pressure unit |
| barg | Bar gauge | Atmospheric pressure | 0 barg = atmospheric | Industrial gauges, hydraulic & pneumatic systems |
| bara | Bar absolute | Perfect vacuum | ~1.01325 bara = atmospheric | Process engineering, thermodynamics, vacuum systems |
| PSIG | PSI gauge | Atmospheric pressure | 0 PSIG = atmospheric | U.S. industrial gauges, hydraulic systems |
| PSIA | PSI absolute | Perfect vacuum | ~14.696 PSIA = atmospheric | U.S. process engineering, thermodynamics |
Relationship between gauge and absolute units. At sea level: bara = barg + 1.01325 | PSIA = PSIG + 14.696.
BARG to PSI Formula
The conversion from barg to PSIG uses the same factor as bar to PSI, because both are gauge pressure measurements. The reference point (atmospheric pressure) cancels out in the conversion.
Exact factor: 1 bar = 14.5038 PSI | 1 PSI = 0.0689476 bar
Example: 25 barg × 14.5038 = 362.6 PSIG | 3,000 PSIG ÷ 14.5038 = 206.8 barg
To convert barg to PSIA (absolute), first convert to PSIG using the formula above, then add the atmospheric pressure baseline: PSIA = (barg × 14.5038) + 14.696. This is rarely needed for hose and fitting selection, which always uses gauge pressure.
BARG to PSI Reference Chart
The following chart covers barg values from low-pressure pneumatic systems through ultra-high-pressure hydraulic applications. All PSI values are PSIG (gauge), matching industrial gauge readings.
| barg | PSIG | Typical Application |
|---|---|---|
| 1 barg | 14.5 PSIG | Low-pressure pneumatics, light air systems |
| 3 barg | 43.5 PSIG | Low-pressure compressed air circuits |
| 5 barg | 72.5 PSIG | Compressed air systems, pneumatic tools |
| 7 barg | 101.5 PSIG | Standard shop air (European specification) |
| 10 barg | 145 PSIG | Light hydraulic circuits, high-pressure air |
| 16 barg | 232 PSIG | Low-pressure hydraulic return lines |
| 25 barg | 362.6 PSIG | Medium hydraulic systems |
| 40 barg | 580.2 PSIG | Industrial hydraulic circuits |
| 63 barg | 913.7 PSIG | Medium-high-pressure hydraulics |
| 100 barg | 1,450 PSIG | High-pressure hydraulic systems |
| 160 barg | 2,321 PSIG | Standard mobile hydraulics (European spec) |
| 207 barg | 3,002 PSIG | SAE 100R2 equivalent working pressure |
| 250 barg | 3,626 PSIG | High-pressure industrial hydraulics |
| 315 barg | 4,568 PSIG | Very high-pressure hydraulics |
| 350 barg | 5,076 PSIG | Ultra-high-pressure systems |
| 420 barg | 6,091 PSIG | Specialty high-pressure hose |
All PSI values are gauge (PSIG). Conversion factor: 1 barg = 14.5038 PSIG. Source: NIST — SI Units and Conversion Factors.
Gauge vs. Absolute Pressure in Industrial Systems
The distinction between gauge and absolute pressure is fundamental to interpreting pressure specifications correctly. Nearly all industrial pressure gauges — including those on hydraulic systems, compressors, and pressure vessels — read gauge pressure (PSIG or barg). The gauge is calibrated to read zero at atmospheric conditions, not at vacuum.
When Absolute Pressure (bara / PSIA) Is Used
Absolute pressure is used in thermodynamic calculations, process engineering (particularly where vacuum or near-vacuum conditions exist), and in the specification of pump NPSH (net positive suction head). For the vast majority of hydraulic hose, fitting, and industrial fluid power work, gauge pressure is the correct reference.
Practical Impact on Hose Selection
When a hydraulic hoseis rated at 207 barg working pressure, that rating is in gauge units. It means the hose can handle 207 bar above atmospheric continuously. Converting to PSIG: 207 × 14.5038 = 3,002 PSIG — consistent with a 3,000 PSIG SAE rating. The small difference is rounding.
How Barg Applies to Hydraulic Hose Selection
When sourcing hydraulic hosefor European-spec equipment or systems documented in metric units, the working pressure will typically be expressed in barg. The selection process is identical to PSI-based selection — the hose working pressure rating must meet or exceed the system maximum operating pressure.
Matching Barg Ratings Across Components
All components in a hose assembly — the hose body, end fittings, and any adapters — must be rated at or above the maximum system pressure. A hose rated at 250 barg paired with fittingsrated at 200 barg creates an assembly limited to 200 barg. The lowest-rated component governs the assembly rating.
SAE vs. ISO Pressure Standards
| Standard | Region | Pressure Unit | Example Rating |
|---|---|---|---|
| SAE J517 | North America | PSI (gauge) | SAE 100R2AT: 3,000 PSIG WP |
| ISO 1436 | International | bar (gauge) | ISO 1436 Type 2: 250 barg WP |
| DIN 20022 | Europe | bar (gauge) | DIN 20022 2SN: 250 barg WP |
| EN 857 | Europe | bar (gauge) | EN 857 2SC: 400 barg WP |
SAE and ISO/DIN standards express working pressure in gauge units. Source: SAE International | ISO Standards.
Frequently Asked Questions
Barg stands for bar gauge— a unit of pressure measured relative to atmospheric pressure. It is the metric equivalent of PSIG. Most industrial pressure gauges read in gauge pressure, making barg the standard unit in hydraulic and pneumatic system specifications outside North America.
Multiply the barg value by 14.5038to get PSIG. Example: 25 barg × 14.5038 = 362.6 PSIG. To convert PSIG back to barg, divide by 14.5038.
Numerically, yes — when both refer to gauge pressure. The difference is contextual clarity. Barg explicitly specifies gauge pressure, while "bar" alone can be ambiguous. In industrial and engineering specifications, barg is preferred to eliminate any confusion between gauge and absolute pressure.
Barg (bar gauge) is measured relative to atmospheric pressure — it is what your gauge reads. Bara (bar absolute) is measured relative to a perfect vacuum. At sea level: bara = barg + 1.01325. Hydraulic hose and component working pressure ratings always use gauge pressure (barg), not absolute.
10 barg equals 145 PSIG(10 × 14.5038 = 145.038). This is in the range of light-to-medium hydraulic systems and high-pressure compressed air circuits.
Hydraulic hose working pressure ratings are always expressed in gauge pressure(PSIG or barg). The rating represents the maximum continuous pressure above atmospheric that the hose is approved for. This matches what an installed pressure gauge reads during system operation.
207 barg equals approximately 3,002 PSIG(207 × 14.5038). This is the bar equivalent of a 3,000 PSI SAE 100R2 hydraulic hose working pressure rating — the minor difference is rounding between standards.