Mpa to Psig Conversion - MPa(g) to psig, psia, atm

An mpa to psig conversion turns a gauge pressure reading in megapascals into pounds per square inch gauge, and back. It uses the fixed relationship that 1 MPa equals exactly 1,000,000 pascals and 1 psi equals exactly 6,894.757293168 pascals, so 1 MPa(g) equals 145.0377377 psig. The result is exact because both sides read zero at atmosphere.

• • Hydraulic accumulators and high-pressure circuits: Translate a 20 MPa(g) accumulator pre-charge or relief valve setting into the psig value on a US gauge or pump datasheet.
• • Hydrostatic and leak-test pressure records: Convert the MPa(g) hold pressure from a European test chart into psig for North American inspection logs and code-compliance paperwork.
• • SCUBA, SCBA, and breathing-air cylinder ratings: Read a 30 MPa(g) or 35 MPa(g) fill pressure on a SCBA cylinder against the same nominal pressure quoted in psig on US spec sheets.

The MPa is a metric pressure unit defined by ISO 80000-4:2019 as exactly 1,000,000 pascals, and the pound per square inch is a US customary unit defined by NIST SP 811 as exactly 6,894.757293168 pascals. The MPa(g) to psig ratio is fixed at 145.0377377, with no uncertainty.

When the source value is already a bar(g) reading instead of an MPa(g) reading, Bar to Psig Conversion Calculator applies the same gauge semantics with a 14.5037738 psig per bar(g) factor that is ten times smaller than the MPa version.

The conversion is a single exact ratio built from the NIST definition of the psi and the ISO definition of the MPa, with both sides sharing the same gauge reference. Multiplying an MPa(g) value by 145.0377377 gives the psig value, and dividing a psig value by 145.0377377 gives the MPa(g) value.

• p(MPa(g)): Pressure in megapascals gauge, the amount by which the absolute pressure exceeds standard atmospheric pressure. The standard input for high-pressure hydraulic, accumulator, and SCUBA readings.
• p(psig): Pressure in pounds per square inch gauge, the amount by which the absolute pressure exceeds standard atmospheric pressure. The standard US customary gauge reading.
• direction: Toggle that picks MPa(g) to psig or psig to MPa(g) so the same tool handles both directions.

When the direction toggle is set to MPa(g) to psig, the calculator multiplies the input by 145.0377377 and reports the answer in psig. The same MPa(g) value drives the cross-check rows, so a round trip returns the same input without precision loss.

According to NIST SP 811, 1 psi = 6,894.757293168 pascals and standard atmosphere = 14.696 psi

For a broader MPa-side panel that also covers bar, psi, atm, torr, pascals, and kilopascals in one entry, MPa Conversion Calculator reads the same MPa input against the full SI prefix ladder.

Four ideas explain the conversion: an exact ISO 80000-4 factor for the MPa, an exact NIST factor for the psi, the shared gauge reference, and the way psia, kPa(g), and atm sit on the same scale.

Once the four ideas are clear, every MPa(g) to psig calculation becomes a single multiplication by 145.0377377 or a single division by the same factor. The gauge reference is what makes the ratio exact.

When the workflow needs to compare MPa(g) and psig against atm, torr, mmHg, and Pa in one entry, Pressure Converter sits next to the MPa to psig conversion as the cross-unit overview.

The mpa to psig conversion calculator has a value field and a direction toggle. Pick the direction, type the gauge reading, and read the converted pressure plus the psia, kPa(g), and atm rows.

1. 1 Pick the conversion direction: Use the dropdown to switch between MPa(g) to psig and psig to MPa(g). The default is MPa(g) to psig for the most common hydraulic, accumulator, and SCUBA workflow.
2. 2 Type the gauge reading: Enter the value in the unit set by the direction toggle. Try 1 for a quick sanity check, 0.689 for a typical car tire, 20 for a hydraulic accumulator, or 35 for a SCUBA fill pressure.
3. 3 Read the converted gauge pressure: The black box at the top of the result panel shows the answer in the target gauge unit. For 1 MPa(g), the answer is 145.0377377 psig; for 145.0377377 psig, the answer is 1 MPa(g). The unit label switches with the direction toggle.
4. 4 Cross-check the psia, kPa(g), and atm rows: The result panel also shows the same pressure in psia (gauge plus 14.696 psi atmosphere), in kPa(g) (MPa(g) multiplied by 1000), and in standard atmospheres. Compare against a published chart to confirm the 145.0377377 factor is being applied correctly.
5. 5 Switch direction for the reverse: Toggle the direction dropdown to flip between MPa(g) to psig and psig to MPa(g). The same value and cross-check rows are kept, so a round trip takes two clicks and never loses precision.

A hydrostatic test report lists 17.5 MPa(g) hold pressure. Toggle to MPa(g) to psig and type 17.5. The calculator returns 2538.160 psig alongside 17,500 kPa(g) and 173.71 atm absolute. Toggle back and the same value rounds to 17.5 MPa(g).

For a broader psi-side panel that also covers kPa, bar, atm, and MPa in a single entry, PSI Conversion Calculator applies the same NIST pascal definitions to the full psi family.

The advantage of a single, factor-driven mpa to psig conversion is that the result is exact, the cross-check rows are reference-aware, and the same tool handles both directions on a 145x magnitude gap.

• • Exact NIST and ISO factor: The 1 MPa(g) = 145.0377377 psig ratio is fixed by the NIST and ISO pascal definitions, so the calculator returns the same value at any precision with no empirical calibration needed.
• • Bidirectional in one tool: Switch the direction toggle to flip between MPa(g) to psig and psig to MPa(g). The same input and cross-check rows stay in place, so a round trip never loses precision.
• • Three reference-aware cross-check rows: Every result includes the same pressure in psia, kPa(g), and atm absolute, so a 1 MPa(g) reading of 159.7337377 psia, 1000 kPa(g), and 10.86923267 atm absolute sits next to its 145.0377377 psig value.
• • Worked hydraulic and SCUBA examples: The 1 MPa(g) reference, the 20 MPa(g) hydraulic accumulator, and the 35 MPa(g) SCUBA tank are built into the explanation, covering pump datasheets, regulator specs, and high-pressure cylinder work.

These benefits apply whenever an MPa(g) reading crosses a US customary workflow. Hydraulic pressure tests, hydrostatic test charts, and SCUBA cylinder ratings all share the same 145.0377377 factor.

For the kPa(g) cross-check row that also covers psi, bar, atm, mmHg, mbar, and MPa, kPa Conversion reads the same pressure against the full kilopascal family.

The mpa to psig conversion is exact, but the usefulness of any specific number depends on what the input represents, the precision of the original reading, and whether the source and destination use the same gauge reference.

• • The MPa is an SI accepted unit rather than a strict SI base, and the SI base for pressure is the pascal. A few engineering datasheets still quote bar or psi, so always check the unit the rest of the system expects.
• • The 145.0377377 factor is exact, but the real pressure being measured is not. A 20 MPa(g) accumulator pre-charge is a single cold snapshot, and the actual pressure rises with temperature and falls with nitrogen permeation.

Atmospheric pressure is the most useful benchmark for a real value. At 0.101325 MPa(a), the atmosphere reads 14.696 psi, the same number that anchors US weather reports, altimeter settings, and SCUBA tank ratings, and the step that turns 1 MPa(g) into 1.01325 MPa(a).

According to ISO 80000-4:2019, 1 MPa = 1,000,000 pascals; 1 atm = 101,325 pascals

As published by BIPM SI Brochure, pascal is the SI unit of pressure and the standard atmosphere is exactly 101,325 pascals

For the related bar-to-psi path that uses the same 14.5037738 factor without the gauge suffix, Bar to PSI Conversion covers the same bar pressure conversion in absolute terms for tire placards and SCUBA ratings.