Convert Pressure from megapascals to pounds per square inch (MPa to psi)

Megapascal to Pound per Square Inch Conversion Formula

To convert a pressure or stress from megapascals (MPa) to pounds per square inch (psi), multiply by 145.04.

• psi = MPa × 145.04

The factor is a thousand times the kilopascal one, because a megapascal is a thousand kilopascals: 1,000,000 ÷ 6,894.76 = 145.0377 psi. Going back the other way, divide by 145.04 — or multiply by 0.006895.

The anchor most people already know sits at the bottom of the scale:

• 0.1 MPa = 14.50 psi — one bar, roughly one atmosphere.
• 1 MPa = 145.04 psi, so 7 MPa is almost exactly 1,000 psi.

Step-by-Step Example

A Japanese hydraulic power unit is rated for 21 MPa continuous working pressure, and a US hose supplier quotes hose in psi:

1. Take the pressure: 21 MPa
2. Multiply by 145.04: 21 × 145.04 = 3,046 psi

That number is not a coincidence. 21 MPa and the American 3,000 psi rating are the same industry standard expressed in two systems, which is why 3,000 psi hose is the correct match rather than an approximation.

Quick Reference Table

High Pressure, Two Vocabularies

Wherever pressure runs into the thousands of psi, the metric world writes MPa and the American world writes psi, so this conversion governs the specification of hydraulics, concrete, pipelines and high-pressure water. Hydraulics is the most standardized: the common working pressures line up as 21 MPa ↔ 3,000 psi, 35 MPa ↔ 5,000 psi and 70 MPa ↔ 10,000 psi, pairs worth memorizing because they recur on every pump, hose and fitting catalog. Concrete is the widest-reaching: a C30 mix means 30 MPa characteristic strength, which an American mix design would call 4,351 psi and round to the familiar 4,000 psi class — near enough that the two grades are often treated as equivalent, and different enough that a structural check should convert rather than assume. Waterjet cutting occupies the extreme, where a 414 MPa pump is sold in the United States as 60,000 psi.

Because the numbers grow large, the failure mode here is not arithmetic but magnitude. A slipped prefix turns 21 MPa into 21 kPa, and 3,046 psi into 3 psi — a difference between a working hydraulic system and a barely inflated balloon. The habit that catches it is to check the answer against the nearest anchor above before using it: anything in industrial hydraulics should land in the thousands of psi, and anything that does not has lost a prefix somewhere.

How many megapascals are in one pound per square inch? One pound per square inch (psi) contains 0.0068947600004501395751 megapascals (MPa) — the inverse of the factor above. Multiplying by 145.03768078 takes you from megapascals to pounds per square inch; multiplying by 0.0068947600004501395751 brings you back.

Put in words: one megapascal equals 145.03768078 pounds per square inch, so the megapascal is the larger unit of this pair. Converting between them never changes the amount of pressure being measured — only the size of the unit you count it in.

What is a megapascal (MPa)?

If you've ever looked at engineering specifications, construction materials, or high-pressure equipment, you've likely seen the term 'MPa.'

A megapascal (MPa) is a unit of pressure in the metric system, equal to one thousand kilopascals (1000 kPa).

The plural form is megapascals.

Using MPa to Measure Material Strength

The megapascal (MPa) is a fundamental unit for quantifying the strength of materials in engineering and construction.

It is commonly used to express a material's ultimate tensile strength (the maximum stress it can withstand while being pulled apart) and compressive strength (its resistance to being squeezed).

For example, structural steel might have a tensile strength of 400 MPa. In comparison, high-performance concrete can have a compressive strength exceeding 80 MPa.

MPa to PSI and Bar Conversions (and kPa)

Understanding how to convert megapascals to other pressure units is crucial for global applications.

Here are the most common conversions:

• 1 MPa = 1,000 kilopascals (kPa)
• 1 MPa = 145.04 pounds per square inch (PSI)
• 1 MPa = 10 bar

The pound per square inch (PSI) is a unit commonly used in the United States for measuring tire pressure and hydraulic systems.

The bar is a unit often used in Europe for weather forecasting and scuba diving.

Real-World Examples of Megapascal Pressures

Megapascals are used to describe immense pressures found in both natural and industrial settings.

The water pressure at the bottom of the Mariana Trench, the deepest point in the ocean, is about 108.6 MPa.

In industry, a high-pressure waterjet cutter operates at pressures ranging from 200 to 600 MPa, demonstrating enough force to slice through metal and stone.

What is a pound per square inch (psi)?

A pound per square inch (PSI) is a unit of pressure commonly used in the imperial system (which is standard in the United States).

It measures the amount of force applied over a single square inch of area.

Common Examples of PSI (Where is PSI Used?)

PSI is a critical measurement for safety and performance in many common items, including:

• Vehicle Tires: Proper tire pressure (PSI) ensures optimal handling, fuel efficiency, and tire life. You can find the recommended level on a sticker inside the driver's door.

• Home Water Pressure: Affects everything from shower performance to how well appliances like dishwashers and washing machines function.

• Sports Equipment: Items like footballs, basketballs, and soccer balls require a specific PSI to perform correctly and safely.

• Tools: Air compressors, pressure washers, and paint sprayers all have specific PSI ratings for safe and effective operation.

Converting PSI to Metric Units like Pascals and Bar

While PSI is standard in the imperial system, scientific and international contexts use metric (SI) units like the Pascal (Pa) and the bar.

• PSI to Pascal (Pa): The official SI unit for pressure.
  1 PSI ≈ 6,894.76 Pascals (or 6.895 kilopascals, kPa).

• PSI to Bar: A common unit in automotive and weather contexts. 1 bar is roughly equal to atmospheric pressure at sea level.
  1 PSI ≈ 0.0689 bar.

Understanding the Types of PSI: PSIG, PSIA, and PSID

The term "PSI" can be specified further to give more context:

• PSIG (Pound-force per square inch gauge): Measures pressure relative to the surrounding atmospheric pressure. This is the most common measurement, used by a standard tire gauge.

• PSIA (Pound-force per square inch absolute): Measures pressure relative to a perfect vacuum (absolute zero pressure).
  The formula is: PSIA = PSIG + local atmospheric pressure.

• PSID (Pound-force per square inch differential): Measures the difference in pressure between two separate points in a system, such as across a filter or valve.

megapascal to pound per square inch Conversion Table

Here are some quick reference conversions from megapascal (MPa) to pound per square inch (psi):

This conversion in other languages

Engineering datasheets across Europe write megapascal to pound per square inch several different ways. The calculation is the same in every one of them.