MPa to PSI Converter: Formula and Chart

To convert MPa to psi, multiply the MPa value by approximately 145.03773773. One megapascal is about 145.0377 pounds per square inch. Use the conversion calculator below for either direction, and then refer to the chart for some commonly used values. Hold the pressure reference with your result: gauge stays gauge, and absolute stays absolute.

How to Convert MPa to PSI

MPa to psi conversion uses a fixed multiplier: psi = MPa × 145.03773773, with the displayed factor rounded. Simply enter the number, choose one of the directions, and enter the result along with its unit. The converter modifies the scale, however, it doesn’t modify the definition of the measurement.

Megapascal to pound-force per square inch converter

Convert between megapascal and pound-force per square inch. The unit changes; the measured quantity does not.

Value FromMPa · megapascalpsi · pound-force per square inch Swap ToMPa · megapascalpsi · pound-force per square inch

Result

145.0377

psi

1 MPa = 145.0377 psi

Unit conversion preserves the pressure reference. Gauge stays gauge and absolute stays absolute; confirm an unspecified reference from the source.

For example, 0.6 MPa × 145.03773773 gives approximately 87.0226 psi. For 5 MPa, the result is 725.1887 psi. To test your result, divide the answer by the same factor and check to see if you ended up with the original value, as long as we take into account the decimal places visible on the screen.

The factor comes from definitions, rather than a measured steel property. One inch is exactly 0.0254 m, while one pound-force is exactly 4.4482216152605 N. Those values yield 1 psi ≈ 6894.757293168 Pa. Dividing 1,000,000 Pa by that number gives the MPa-to-psi multiplier. See NIST’s conversion-factor table and its pound-force definition in footnote 23.

Quick-check mistake: 145 is a much more convenient number than a precise value for the conversion factor. Someone doing a quick check to see if two numbers given are of a similar order of magnitude may find it useful. A worksheet containing many calculations should keep the precise multiplier until the very last.

Converting 1 MPa to around 145.0377 psi converts the same physical amount to a new measurement system. The result of multiplication is the forward conversion, and the result of division is the conversion back to MPa. Your copied conversion record requires the original quantity and pressure reference because neither can be recovered from the number.

MPa to PSI Conversion Table

This pressure conversion table lists 18 values from 0.01 to 100 MPa. Every result uses the definition-derived factor and is rounded to four decimal places. The rows include 0.1 MPa to psi, 0.8 MPa to psi and 1.5 MPa to psi conversions. Select the matching input rather than shifting a decimal by eye, and keep the original document available when recording the converted figure.

Four decimal places simplify checking of calculations. However, they don’t communicate how accurately a gauge measured pressure. Showing 0.6 MPa and calculating 87.0226 psi doesn’t establish four-decimal-place measurement accuracy. Indicate that this is a calculated value if the distinction is important.

For a spreadsheet, place the MPa input in cell A2 and use =A2*1000000*0.0254^2/4.4482216152605. Format the display separately from the stored value. That approach preserves intermediate digits when subsequent cells use the conversion.

Convert PSI to MPa

If you wish to convert psi to MPa, divide the psi value by approximately 145.03773773, or multiply it by approximately 0.006894757293. The same calculator works in reverse. Verify the direction of your input, especially if the supplier’s document and your worksheet use different pressure units for the same quantity.

The reverse conversion formula gives 100 psi ≈ 0.6895 MPa, 1000 psi ≈ 6.8948 MPa, and 4000 psi ≈ 27.5790 MPa. Multiplying a psi input by 145 instead would produce a much larger number in the wrong direction. No separate material factor is needed for steel.

Suppose the worksheet indicates 1000 psi and the accompanying narrative states 6.9 MPa. Values are close after rounding, but the conversion alone can’t determine if their references, measurement points, or revision dates are the same. Verify the fields before you treat them the same way as equivalent requirements.

4000 psi converts to approximately 27.5790 MPa by division. Reversing the operation restores about 4000 psi, subject to display rounding. The calculation works for megapascals and pounds per square inch in either direction, while the source document continues to define the quantity being compared.

What MPa and PSI Mean

A megapascal is a million pascals. A pascal, denoted by Pa, is the SI unit of pressure and is equal to one newton per square meter. PSI means pounds per square inch, more precisely pound-force per square inch. Each pressure unit represents force per area, using a different numerical scale.

In the BIPM’s concise SI Brochure, the pascal and the prefix mega are listed in the unit tables. The International System of Units dictates that in MPa, M matters, and therefore MPa means megapascal. The same approach is required for mechanical drawings, spreadsheets, and technical inquiries.

• 1 MPa = 1000 kPa = 1,000,000 Pa.
• 1 MPa = 10 bar. Bar is another unit from MPa.
• 1 ksi = 1000 psi. A result that’s stated in ksi must not be copied to a psi field without changing the value.

To convert megapascal values, first ascertain the destination unit. For example, 10 MPa is 100 bar, but approximately 1450.3774 psi. Confusing bar with psi creates a scale error before any question of rounding arises. For dimensional entries on the same document, use the separate millimeter-to-inch conversion guide.

MPa, PSIG and PSIA: Keep the Reference

Converting MPa to psi retains the pressure reference. Absolute pressure uses a vacuum reference. Gauge pressure is pressure relative to atmospheric pressure. The difference is signaled by tags such as psig and psia. Without such a tag, the source’s use of MPa or psi is ambiguous.

In its chapter on pressure measurement, OpenStax says absolute pressure equals gauge pressure plus atmospheric pressure. Consequently, a conversion from gauge to absolute pressure requires an atmospheric pressure value expressed in the same units. The fixed MPa-to-psi ratio can’t provide that.

For a gauge-marked source, 1 MPa converts to approximately 145.0377 psi, gauge. For an absolute-marked source, 1 MPa converts to approximately 145.0377 psi, absolute. The numbers match because the unit conversion is the same; the reference descriptions remain different.

When a request simply states “10 MPa,” leave this as is and state the reference as unspecified. It’s the source owner who must clarify whether a psig result is to be provided. Don’t simply add 14.7 psi; atmospheric pressure isn’t constant, and an assumed offset would mean a change to the pressure reference rather than simply converting units.

At 1 MPa, the reference-preserving result is approximately 145.0377 psi. A gauge-to-absolute comparison also requires atmospheric pressure, so the conversion factor isn’t sufficient on its own. Worksheets should keep a separate reference field and leave it unspecified if the original record doesn’t state whether the pressure is gauge or absolute.

Rounding and Measurement Precision

Keep sufficient digits for intermediate calculations and choose a final display consistent with the source precision and intended use. Calculators can provide extra digits without affecting measurement accuracy. For a specified tolerance, preserve the original limits; don’t replace them with a roughly rounded converted tolerance.

NIST’s guidance on rounding converted values connects the result to the source rounding error and the function of the conversion. JCGM 100, section 7.2.6 also distinguishes final reporting precision from digits retained to avoid rounding errors in subsequent calculations.

The last column subtracts the definition-derived value from the result calculated with 145. Negative numbers indicate that the smaller factor yields the lower result. At 100 MPa the difference is about 3.7738 psi. Using 145.038 instead gives an approximately 0.0262 psi difference at that input. These are arithmetic differences, not estimates of instrument error.

Consider an illustrative requirement of 10.00 ±0.05 MPa. Its original limits are 9.95 and 10.05 MPa. Their calculated displays are about 1443.1255 and 1457.6293 psi. Writing “1450 ±7 psi” would produce different limits, 1443 and 1457 psi. In this situation, we would keep the original requirement as it is, rather than using the rounded value of the interval.

The QA staff should understand the difference between a stated tolerance and a measurement uncertainty. The ± sign doesn’t indicate which is being stated. In such instances, it’s important to keep the original instructions and the label of the source without deriving a measurement uncertainty from the number of digits.

The 10.00 ±0.05 MPa example illustrates why converting limits needs care: its upper limit displays as approximately 1457.6293 psi, whereas 1450 ±7 psi ends at 1457 psi. Reference conversions can help colleagues read a document, but rounded displays shouldn’t silently replace its original acceptance limits.

Pressure and Stress in Steel Documents

Pressure and mechanical stress are both expressed in MPa or psi, but a unit that’s shared by both doesn’t mean they’re the same. Preserve the converted value adjacent to a definition of tensile strength. After conversion, tensile strength is tensile strength and not a pressure rating for a pipe or flange. Confusion starts when the quantity label is lost.

“It is therefore important not to use the unit alone to specify the quantity.”

For a purely illustrative example, entering a value of 400 MPa in the tensile strength field yields about 58,015.0951 psi or 58.0151 ksi. While this value alone does not establish the pressure capability of a fabricated part, retain “tensile strength” with the number and maintain the material certificate reference.

For the next query regarding flange pressure and temperature, one should refer to the separate flange pressure-rating resource. As far as engineering is concerned, this (i.e. unit conversion) and the existing weld-neck rating calculator have been made separately, and the rating calculator requires class, material group, and temperature, and this article doesn’t validate the rating.

A 400 MPa strength value is approximately 58.0151 ksi when converted. The two values represent the same named material property. Reading the number as a component pressure rating changes the question, so comparisons between steel records should retain the property name and the governing document along with the number.

Carry Pressure Units into a Steel Enquiry

A pressure handoff that retains the named quantity, original value, unit, reference and controlling document is an adequate starting point. It should be noted that, where it’s helpful to the end user, the reference conversion should be inserted. The record shown which accompanies the value is an editorial aid, a communication draft, and not a metrological calibration certificate or proof of metrological traceability.

This can assist the buying department in assigning meaning to the data in the record. The QA department can confirm that the specified tolerance was maintained. The plant personnel can ensure that the measurement label and reference weren’t changed because of translation or abbreviation. If a field is stated missing, mark it as missing.

According to ASTM’s editorial advice regarding SI units, some combined standards handle SI and inch-pound values separately. As such, the prescribed numbers need not be exact equivalents. Please read the applicable document’s unit provisions. Do not mistakenly make both a converted display and an original value co-controlling.

When requesting a component, insert the original specification in the flange specification line or the pipe-fitting enquiry record. This site’s conversion tool will help your colleagues read the pressure unit. Product suitability hinges on the actual component requirements.

An enquiry at 10.00 MPa indicates that the converted display of about 1450.3774 psi contains only one field. Keeping the original number, pressure reference, and specification, disallows the reader from treating this isolated number as a complete requirement. Share those fields with Synbase Steel while discussing the relevant product family.

Frequently Asked Questions

What does 1 MPa equal in PSI?

One MPa equals approximately 145.0377 psi. Multiply a value in megapascals by about 145.03773773 to calculate pounds per square inch, or use the online converter for the reverse direction. The shortened factor 145 is an estimate. When copying the answer, preserve the original pressure reference and distinguish the calculator’s displayed digits from the precision of the measurement that supplied the input. A unit conversion can’t improve that measurement. Retain the source value alongside the converted display for comparison and checking.

What is 4000 PSI to MPa?

4000 psi is approximately 27.5790 MPa. Divide 4000 by about 145.03773773, or multiply it by about 0.006894757293. Both operations express the same pressure conversion in opposite forms. A source marked gauge remains gauge after this calculation, and an absolute value remains absolute. If the source only says psi, keep the reference unspecified until its document or owner clarifies the intended meaning of the original number in context. The unit symbol alone supplies no missing pressure reference for this comparison.

What does 1 MPa mean?

One MPa means one megapascal, equal to 1,000,000 pascals or 1000 kilopascals. The same unit can be used to describe pressure or stress, so the label beside the number matters when reading a steel document. A pressure reading, a tensile-strength value, and a specified limit each require their own descriptions, even if each is given in MPa on the same printout.

What are bar, PSI and MPa?

Bar, PSI and MPa are different units used to express pressure. One MPa equals 10 bar and approximately 145.0377 psi. None of those unit names, used alone, establishes whether a value is gauge or absolute. Keep a separate reference label when the application requires it.

Does MPa to PSIG need a different factor?

The MPa-to-psi factor stays the same when the original pressure is already gauge. A value explicitly described as 1 MPa gauge becomes approximately 145.0377 psig. If the original value is absolute or its reference is unknown, unit conversion alone can’t produce a justified gauge-pressure result.

Can I use this conversion for steel strength?

Yes. The same factor converts stress in MPa to psi. Keeping the property name avoids mistaking strength for the component pressure rating. Keep the material certificate reference beside the converted result so readers can identify the property and its source.

References & Sources

• NIST, SP 811 Appendix B.8: conversion factors. Unit definitions and conversion basis.
• NIST, SP 811 footnotes 22–23. Exact mass and force factors.
• NIST, SP 811 Appendix B.7.2. Rounding converted numerical values.
• BIPM, concise SI Brochure, version 4.01. Pascal, prefixes and quantity identification.
• OpenStax, College Physics 2e, section 11.6. Gauge and absolute pressure definitions.
• JCGM 100:2008, section 7. Reporting measurement results and uncertainty.
• ASTM, Using SI Units in ASTM Standards. Some historical examples of published unit systems combined.