Convert Pressure from Inches of mercury to megapascals (inHg to MPa)

Inch of mercury to megapascal Conversion Formula

Example

Let's convert 5 Inch of mercury (inHg) to megapascal (MPa).

Using the formula:

Therefore, 5 Inch of mercury (inHg) is equal to 0.016931944766305439265 megapascal (MPa).

How many inches of mercury are in one megapascal? One megapascal (MPa) contains 295.29980572284863811 Inches of mercury (inHg) — the inverse of the factor above. Multiplying by 0.0033863889532610878529 takes you from inches of mercury to megapascals; multiplying by 295.29980572284863811 brings you back.

Put in words: one inch of mercury equals 0.0033863889532610878529 megapascals, so the inch of mercury is the smaller 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 an Inch of Mercury (inHg)?

An inch of mercury, often abbreviated as inHg, is a unit of pressure.

It is not part of the standard metric (SI) system but is widely used in the United States and in specific fields like meteorology and aviation.

The unit is defined by its name: it is the amount of pressure exerted by a column of liquid mercury exactly one inch tall at a standard temperature.

Where is inHg Used?

You will most commonly encounter inches of mercury in a few key areas:

• Weather Reporting: In the U.S., inHg is the standard unit for reporting barometric pressure (also known as atmospheric pressure).
  A "high" pressure system indicating clear weather might be around 30.50 inHg, while a "low" pressure system associated with storms could be 28.50 inHg.

• Aviation: This measurement is critical for pilot safety.
  Pilots use the local barometric pressure (in inHg) to calibrate their altimeters—instruments that measure altitude—to ensure they are flying at the correct height.

• Vacuum Systems: The unit is also widely used in science and industry to measure vacuum pressure.
  This is common in systems like air conditioning, refrigeration, and for monitoring the manifold pressure in piston engines.

How to Convert inHg to Other Pressure Units

Because inHg is not a global standard, it's often necessary to convert it to other pressure units for calculations or international use.

Here are the most common conversions for 1 inHg:

• 0.491154 pounds per square inch (PSI)
• 33.86 millibars (mbar)
• 3,386.39 pascals (Pa)
• 0.000491154 kilopound per square inch (ksi)

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.

Inch of mercury to megapascal Conversion Table

Here are some quick reference conversions from Inch of mercury (inHg) to megapascal (MPa):