Pressure Conversion Inputs
Formula Used
Gauge bar converts directly using the fixed pressure factor. Multiply bar gauge by 14.503773773 to obtain PSIG. This formula needs no atmospheric pressure adjustment value.
Absolute bar first requires atmospheric pressure to be removed. Subtract the atmospheric reference before multiplying by the factor. This converts absolute pressure into a gauge-referenced result correctly.
Reverse conversion divides PSIG by the same conversion factor. Add atmospheric pressure to obtain the absolute bar value. This keeps gauge and absolute references clearly separated always.
How to Use This Calculator
- Enter the pressure value you want to convert.
- Select bar gauge, bar absolute, or PSIG.
- Choose the atmospheric pressure source when required.
- Select precision, notation, and significant figure settings.
- Add range, difference, or batch values optionally.
- Press Calculate to create the complete result report.
Pressure Reference Guide
PSIG measures pressure relative to the surrounding atmosphere. PSIA measures pressure relative to a perfect vacuum. Choosing the correct reference prevents major engineering calculation errors.
Bar gauge works like PSIG and excludes atmospheric pressure. Bar absolute includes atmospheric pressure in the measured value. Always confirm the instrument label before entering measurements here.
Negative PSIG means pressure is below the local atmosphere. This condition is commonly described as partial vacuum pressure. Absolute pressure must never fall below zero physically anywhere.
Worked Examples
| Bar Type | Bar Value | Atmospheric Pressure | Result |
|---|---|---|---|
| Gauge | 1 bar(g) | Not required | 14.5038 PSIG |
| Gauge | 5 bar(g) | Not required | 72.5189 PSIG |
| Absolute | 1.01325 bar(a) | 1.01325 bar | 0 PSIG |
| Absolute | 2 bar(a) | 1.01325 bar | 14.312 PSIG |
Frequently Asked Questions
How many PSIG are in one bar?
One bar gauge equals approximately 14.503773773 PSIG. The conversion uses a fixed international pressure relationship. Rounded results depend on your selected decimal precision setting.
Is bar normally gauge or absolute?
The word bar alone does not confirm reference type. Instruments may report gauge or absolute pressure values. Check labels like barg, bara, bar(g), or bar(a).
What is the difference between PSI and PSIG?
PSI is a general pressure unit description. PSIG specifically references pressure against local atmospheric pressure. The reference determines whether atmospheric pressure is already excluded.
How do I convert bar absolute to PSIG?
Subtract atmospheric pressure from the absolute bar value. Then multiply the remaining gauge bar by 14.503773773. Accurate atmospheric data improves the final PSIG result significantly.
Why must atmospheric pressure be subtracted?
Absolute pressure includes the surrounding atmospheric pressure contribution. PSIG excludes that pressure by using atmosphere as zero. Subtraction aligns both measurements to the same reference basis.
Can PSIG have a negative value?
Yes, PSIG can be negative below local atmosphere. Negative gauge pressure represents a partial vacuum condition. It does not mean absolute pressure becomes physically negative.
What does negative PSIG represent?
Negative PSIG shows pressure lower than surrounding atmospheric pressure. Pumps and vacuum systems commonly produce such conditions. The absolute pressure remains above zero during normal operation.
What is standard atmospheric pressure in bar?
Standard atmospheric pressure equals exactly 1.01325 bar. It also equals approximately 14.6959 pounds per square inch. Local weather and altitude can change actual atmospheric pressure.
Does altitude affect bar-to-PSIG conversion?
Altitude affects conversions involving absolute pressure references. Higher altitude usually means lower atmospheric pressure. Gauge bar conversions remain direct without atmospheric correction requirements.
How accurate is the conversion factor?
The factor uses a high-precision unit relationship. Measurement accuracy still depends on sensors and references. Select suitable precision without implying unrealistic instrument accuracy levels.
Can this calculator convert PSIG back to bar?
Yes, select PSIG as the input pressure type. The calculator returns gauge bar and absolute bar values. Atmospheric pressure determines the absolute result during reverse conversion.