MPa to PSIG Conversion Calculator — Megapascals to Gauge Pressure in PSI
Convert absolute pressure in megapascals (MPa) to gauge pressure in psig (psi gauge). PSIG measures pressure above local atmospheric pressure — essential for hydraulics, pressure vessels and instrumentation.
MPa
psi
Pressure above atmospheric reference — negative means sub-atmospheric (vacuum side)
- 1
Absolute psi (psia)
1 × 145.03774 = 145.03771 MPa = 145.0377 psia (absolute from vacuum) - 2
Subtract atmospheric reference
145.0377 − 14.6959 = 130.3418
How does this calculator work?
psig = MPa × 145.0377 − 14.696. At standard atmosphere, 1 MPa absolute ≈ 130.34 psig. For gauge MPa to psig, multiply by 145.0377 directly — the atmospheric offset cancels. Pressures below 0.101325 MPa absolute give negative psig (sub-atmospheric).
Formula
How this is calculated
Gauge pressure (psig) measures how far a pressure exceeds the local atmospheric pressure, rather than a perfect vacuum. An industrial hydraulic system rated at "1,500 psig" operates 1,500 psi above atmospheric — the absolute pressure is about 1,500 + 14.696 = 1,514.696 psia ≈ 10.443 MPa.
Converting MPa to psig involves two steps: first multiply the absolute MPa value by 145.03773 to get absolute psi (psia), then subtract the atmospheric reference (default 14.6959 psi, the standard atmosphere of 101,325 Pa). Because 1 MPa (1,000,000 Pa) is much greater than 1 atm (101,325 Pa), the psig result is positive for all pressures above 0.101325 MPa: 1 MPa absolute ≈ 145.038 − 14.696 ≈ 130.342 psig.
The atmospheric reference is editable for locations at altitude or with non-standard conditions. At high altitude the local atmospheric pressure is lower, so gauge readings are higher than at sea level for the same absolute pressure. Standard atmosphere (101,325 Pa = 14.696 psi) applies at sea level.
Frequently asked questions
1 MPa (absolute) ≈ 130.342 psig at standard atmosphere (14.696 psi). This is because psia = 1 × 145.0377 = 145.0377 psia, then psig = 145.0377 − 14.6959 = 130.342 psig.
psia is absolute pressure — measured from a perfect vacuum. psig is gauge pressure — measured above local atmospheric pressure (≈ 14.696 psi at sea level). The relationship is: psia = psig + atm_psi. Most industrial gauges read psig; thermodynamic calculations (PV=nRT) require psia.
If your MPa reading is already gauge (MPa g), the conversion simplifies to: psig = MPa_gauge × 145.0377. The atmospheric offsets cancel because 0.101325 MPa × 145.0377 ≈ 14.696 psi.
Also known as
TG we-Calculate Editorial Team. (2026). MPa to PSIG Conversion Calculator — Megapascals to Gauge Pressure in PSI [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/mpa-to-psig-conversion-calculator
TG we-Calculate Editorial Team. "MPa to PSIG Conversion Calculator — Megapascals to Gauge Pressure in PSI." TG we-Calculate. 2026. https://we-calculate.com/calculator/mpa-to-psig-conversion-calculator.
TG we-Calculate Editorial Team, "MPa to PSIG Conversion Calculator — Megapascals to Gauge Pressure in PSI," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/mpa-to-psig-conversion-calculator
@misc{wecalculate_mpa_to_psig_conversion_calculator, title = {MPa to PSIG Conversion Calculator — Megapascals to Gauge Pressure in PSI}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/mpa-to-psig-conversion-calculator}}, year = {2026}, note = {TG we-Calculate} }
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