MPa to psig conversion calculator
Convert absolute pressure in megapascals to gauge pressure in pounds-force per square inch, or work backward from psig to MPa.
Pressure inputs
Live result
Pressure identity details
| Quantity | Value | Unit |
|---|---|---|
| Absolute pressure | 1 | MPa abs |
| Absolute pressure | 145.0377 | psia |
| Standard atmosphere | 14.6959 | psi |
| Gauge pressure | 130.3418 | psig |
How to use the MPa to psig conversion calculator
What this calculator does
This calculator converts an absolute pressure stated in megapascals into pounds-force per square inch gauge, and it also works in reverse. It is useful when an engineering specification gives pressure in MPa absolute but a gauge, data sheet, or operating limit is labeled psig. The conversion is an exact numerical identity within the stated factor and standard-atmosphere assumption; it does not assess whether equipment is safe, calibrated, or suitable for a particular service.
When to use it
Use it to translate a pressure-vessel specification before comparing it with a gauge range, to convert test-bench readings between SI and U.S. customary conventions, to check compressor or hydraulic documentation, or to reconcile an absolute-pressure simulation with a field instrument that reports gauge pressure.
How to calculate
- The calculator opens with a complete demonstration: 1 MPa absolute, which produces 130.3418 psig. Its Excel workbook is ready immediately.
- Replace the value in Absolute pressure to convert from MPa absolute. The Gauge pressure field and every result update live.
- Alternatively, type directly into Gauge pressure to work backward. The calculator updates Absolute pressure using the reciprocal factor.
- Read the main Gauge pressure result, then use Equivalent psia and Atmospheric offset to verify how the reference pressure was handled.
- Select Download Excel to save the current inputs and typed results in a validated OOXML workbook. Reset clears the demonstration and may disable the export until a complete valid value is entered again.
Input guide
Absolute pressure is a required non-negative decimal in MPa absolute. Use a period for decimals, for example 2.5. Higher MPa values produce proportionally higher psig values. Do not paste unit symbols or scientific notation; they are rejected rather than silently changed. The zero point is a perfect vacuum, so this input is not the same as MPa gauge.
Gauge pressure is a decimal in psig referenced to the standard atmosphere. A realistic example is 50 psig. Increasing it increases the reconstructed absolute MPa value. Negative gauge pressure is valid only down to approximately – 14.6959 psig, corresponding to a perfect vacuum under the standard-atmosphere assumption. Values below that boundary are physically incompatible with this model.
Output guide
Gauge pressure is the primary converted result in psig. Zero means the absolute pressure equals the standard atmosphere; a positive result means pressure above atmosphere; a negative result means a partial vacuum. Absolute pressure repeats the canonical MPa value that drives the model. Equivalent psia expresses the same absolute pressure in pounds per square inch absolute. Atmospheric offset is fixed at about 14.6959 psi for this conversion convention. The Pressure identity details table shows all four quantities together so that absolute and gauge references are not confused.
Worked example
For the startup value of 1 MPa absolute, multiply by the reference factor: 1 × 130.3418 = 130.3418 psig. The equivalent absolute pressure is 145.0377 psia, and subtracting the standard-atmosphere offset of about 14.6959 psi gives 130.3418 psig. This matches the first-open result and the values written to the workbook.
Learn more
The NIST pressure conversion table documents the pascal-to-psi relationship. The BIPM SI Brochure explains the International System of Units, including the pascal, while the CGPM definition of the standard atmosphere establishes 101,325 Pa as one standard atmosphere.
Understanding absolute and gauge pressure
Absolute pressure uses a perfect vacuum as zero. Gauge pressure uses the surrounding atmosphere as zero, which is why an ordinary pressure gauge reads about zero when open to the air. In the model used here, psig equals psia minus one standard atmosphere. Real local atmospheric pressure varies with altitude and weather, so high-accuracy field work may require the actual ambient pressure rather than the standard reference used by this conversion.