Bar to PSIG Converter

How to use the Bar to PSIG Converter

What this calculator does. This calculator converts an absolute pressure stated in bar into gauge pressure stated in pounds per square inch gauge, or psig. It first converts bar to absolute psi and then subtracts one standard atmosphere. The result is an exact unit conversion under the stated reference assumption; it is not a substitute for a calibrated field instrument, a local barometer reading, or an engineering safety review.

When to use it. Use it when reading an equipment datasheet that gives absolute pressure in bar but a gauge, specification, or maintenance procedure uses psig; when checking compressor, pneumatic, hydraulic, process, or HVAC values across metric and U.S. customary units; when preparing a calculation sheet for colleagues; or when verifying a hand conversion before entering a setpoint. Because gauge pressure depends on the chosen atmospheric reference, use an instrument-specific or site-specific atmosphere when a procedure requires one rather than the standard value used here.

How to calculate. The converter opens with a complete demonstration of 10 bar abs, so the live result and an example Excel workbook are ready immediately.

1. Replace the value in Absolute pressure with the pressure you need to convert. Use a period as the decimal separator and do not type unit letters into the field.
2. Read Gauge pressure as the main psig result. Review the supporting values for Absolute pressure in psia, Kilopascals, Standard atmospheres, and the Reference atmosphere.
3. Check the Conversion detail table to see the input, the bar-to-psi step, the atmospheric subtraction, and the final gauge value.
4. Select Download Excel to save the current inputs and calculated outputs in a real .xlsx workbook. Select Reset to clear the demonstration value and all calculated content; Excel export then stays disabled until a complete valid pressure is entered again.

Input guide. Absolute pressure is required and accepts a finite non-negative decimal in bar absolute, such as 10, 1.01325, or 250. A value of zero bar absolute is physically a perfect vacuum and produces a negative gauge pressure. Higher bar values increase every absolute-pressure output linearly and increase psig by the same converted increment. Do not enter commas as decimal separators, scientific notation, “bar,” “psi,” or a negative value. The field is intentionally strict so pasted text cannot be silently misread.

Output guide. Gauge pressure is the converted pressure above one standard atmosphere, displayed in psig. A zero result corresponds to one standard atmosphere; a negative result means the absolute pressure is below that reference, not that absolute pressure is negative. Absolute pressure is the same input converted to psia before atmospheric pressure is removed. Kilopascals is the absolute pressure in kPa, with 1 bar equal to 100 kPa. Standard atmospheres compares the absolute input with 101.325 kPa. Reference atmosphere shows the 14.6959 psi subtraction used by the model. The summary pills repeat the current bar, psig, and atmosphere values for quick scanning. The table rows are calculation stages, not separate measurements.

Worked example. For the startup value of 10 bar abs, multiply by 14.5037738 psi per bar to obtain 145.037738 psia. Subtract 14.6959488 psi, the pressure of one standard atmosphere, to obtain 130.341789 psig. Rounded to the display precision, the first-open result is 130.34 psig. The same 10 bar equals 1,000.00 kPa and approximately 9.8692 standard atmospheres. These values appear consistently in the live panel, detail table, and downloadable workbook.

Learn more. NIST publishes a practical pressure and gas-flow conversion table, and its SI conversion-factor appendix states that 1 bar equals 100 kPa. NOAA's explanation of air pressure and standard sea-level pressure provides context for why gauge and absolute pressure differ.