Millimeter of Mercury to Megapascal Converter
Convert millimeters of mercury to megapascals with our free online pressure converter.
Quick Answer
1 Millimeter of Mercury = 0.000133 megapascals
Formula: Millimeter of Mercury × conversion factor = Megapascal
Use the calculator below for instant, accurate conversions.
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All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.
Millimeter of Mercury to Megapascal Calculator
How to Use the Millimeter of Mercury to Megapascal Calculator:
- Enter the value you want to convert in the 'From' field (Millimeter of Mercury).
- The converted value in Megapascal will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Pressure category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Millimeter of Mercury to Megapascal: Step-by-Step Guide
Converting Millimeter of Mercury to Megapascal involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
MPa = mmHg × 0.000133322Example Calculation:
1 mmHg = 0.000133 MPa
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
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Need to convert to other pressure units?
View all Pressure conversions →What is a Millimeter of Mercury and a Megapascal?
The millimeter of mercury (symbol: mmHg) is a manometric unit of pressure.
The Physical Definition: It is defined as the pressure exerted at the base of a column of mercury exactly 1 millimeter high at a temperature of 0°C (32°F) under standard gravity.
Relation to SI Units: 1 mmHg ≈ 133.322387415 Pascals.
mmHg vs. Torr: While the terms are often used interchangeably, there is a tiny technical difference:
- Torr is defined as exactly 1/760 of a standard atmosphere.
- mmHg is based on the physical properties of mercury.
- The difference is roughly 0.000015%. For all medical, engineering, and everyday purposes, 1 mmHg = 1 Torr.
Key standard relationships:
- 1 mmHg = 1 Torr
- 760 mmHg = 1 standard atmosphere (atm)
- 1 mmHg ≈ 1.333 millibars (mbar)
- 1 mmHg ≈ 0.0193 PSI
1 MPa = 1,000,000 Pa = 1,000 kPa = 145.038 PSI = 10 bar = 9.869 atm
Why Megapascal?
MPa is the "sweet spot" for engineering pressures:
- Pascal is too small: 1 Pa = barely measurable (atmospheric is 101,325 Pa)
- Kilopascal is too granular: Engineering specs in kPa are 4-5 digit numbers (20,000 kPa for concrete)
- MPa is optimal: Concrete 20-40 MPa (simple, memorable)
- Engineering standard: All material specs given in MPa
- SI-derived: ISO and international standards use MPa
Note: The Millimeter of Mercury is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Megapascal belongs to the imperial/US customary system.
History of the Millimeter of Mercury and Megapascal
: Torricelli and the Liquid Silver
The mmHg is one of the oldest measurement units still in daily use.
1. The Invention of the Barometer (1643)
Before 1643, people believed suction "pulled" water up pipes. Evangelista Torricelli proved this was wrong. He filled a tube with mercury (which is much heavier than water) and saw it settle at 76 cm. He realized it wasn't a pull, but a "push" from the weight of the invisible atmosphere.
2. Why Mercury?
Mercury was chosen because it is the only metal that is liquid at room temperature and is extremely dense (13.6 times heavier than water). If Torricelli had used water, his barometer would have needed to be over 34 feet (10 meters) tall to measure the same atmospheric weight!
3. The Move to Absolute Values
In the mid-20th century, scientists realized that a "millimeter" of mercury actually weighed more in some places than others (due to gravity differences). To fix this, the Torr was created as a fixed mathematical fraction of an atmosphere, while the mmHg remained as the descriptive name for the liquid measurement.
Common Uses and Applications: millimeters of mercury vs megapascals
Explore the typical applications for both Millimeter of Mercury (imperial/US) and Megapascal (imperial/US) to understand their common contexts.
Common Uses for millimeters of mercury
When to Use megapascals
Materials Engineering: Tensile strength, compressive strength, yield strength - THE standard unit for all material properties. Hydraulics: High-pressure hydraulic systems (construction, manufacturing, heavy equipment). Pressure Vessels: Gas cylinders, boilers, reactors, automotive fuel systems. Geotechnical: Soil bearing capacity, rock strength, foundation design. Aerospace: Structural requirements, component ratings.
Material Strengths (Compressive/Tensile)
Understanding material strength is critical for engineering design:
| Material | Type | Strength (MPa) | Notes | |---|---|---|---| | Styrofoam | Compression | 0.01-0.1 | Very weak, insulation only | | Wood (softwood) | Compression | 20-40 | Pine, spruce, fir typical | | Wood (hardwood) | Compression | 40-60 | Oak, maple stronger | | Brick | Compression | 10-40 | Varies by firing temperature | | Concrete (standard) | Compression | 20-40 | Common 28-day strength | | Concrete (high-strength) | Compression | 50-100 | Pre-stressed applications | | Granite | Compression | 100-250 | Very strong, suitable for columns | | Aluminum alloy (6061) | Tensile | 200-300 | Common structural aluminum | | Aluminum alloy (7075) | Tensile | 500-600 | High-strength aerospace | | Steel (structural ASTM A36) | Yield | 250 | Common building steel | | Steel (high-strength ASTM A572) | Yield | 345-450 | Bridge, crane applications | | Steel (ultra-high) | Tensile | 500-1,000 | Special applications | | Steel cable (wire rope) | Tensile | 1,600-2,000 | Elevators, suspension bridges | | Carbon fiber composite | Tensile | 3,000-7,000 | Aerospace, racing | | Kevlar fiber | Tensile | 3,600-3,800 | Armor, protective gear |
Design factor: Actual working stress = material strength ÷ safety factor (typically 2-4)
Hydraulic Systems (High Pressure)
Hydraulic pressure ratings define system capability:
| System Type | Operating Pressure | Peak Pressure | PSI Equivalent | Application | |---|---|---|---|---| | Automotive brake | 10-15 MPa | 20 MPa | 1,500-2,900 PSI | Car braking force | | Automobile power steering | 10-15 MPa | 20 MPa | 1,500-2,900 PSI | Steering assist | | Construction excavator | 20-35 MPa | 40 MPa | 2,900-5,800 PSI | Digging bucket | | Backhoe | 25-30 MPa | 35 MPa | 3,625-5,075 PSI | Heavy lifting | | Dump truck bed | 20-25 MPa | 30 MPa | 2,900-4,350 PSI | Lifting load | | Industrial press | 20-40 MPa | 50 MPa | 2,900-7,250 PSI | Metal forming | | Hydraulic jack | 50-70 MPa | 80 MPa | 7,250-11,600 PSI | Lifting capability | | Water jet cutter | 200-400 MPa | 450 MPa | 29,000-65,000 PSI | Material cutting | | Oil well pump | 100-200 MPa | 250 MPa | 14,500-36,250 PSI | Deep well pressure |
Pressure Vessels & Storage
Pressure ratings determine safe working limits:
| Vessel Type | Typical Pressure | Material | Working PSIG | |---|---|---|---| | Compressed air tank | 0.8-1.0 MPa | Steel | 116-145 PSI | | Propane BBQ tank | 1.5-2.0 MPa | Steel | 218-290 PSI | | Scuba tank (full) | 20-30 MPa | Aluminum/Steel | 3,000-4,350 PSI | | Natural gas vehicle | 20-25 MPa | Composite | 3,000-3,625 PSI | | Hydrogen fuel cell | 35-70 MPa | Carbon fiber | 5,000-10,000 PSI | | Industrial gas cylinder | 15-20 MPa | Steel | 2,175-2,900 PSI | | Medical oxygen | 13.8-15 MPa | Aluminum | 2,000-2,175 PSI | | Nitrogen (instrument) | 10-13.8 MPa | Steel | 1,450-2,000 PSI |
Safety factor: Pressure vessels typically designed with 4:1 to 6:1 safety margin
Geotechnical Engineering (Soil/Rock)
Foundation and excavation design based on pressure ratings:
| Material/Condition | Bearing Capacity | Suitable For | Notes | |---|---|---|---| | Soft clay | 0.05-0.2 MPa | Temporary structures | High settlement risk | | Medium clay | 0.1-0.3 MPa | Single story | Careful design needed | | Stiff clay | 0.3-0.5 MPa | Multi-story buildings | Good load capacity | | Dense sand | 0.3-0.6 MPa | Foundation base | Excellent for building | | Gravel/sand mixture | 0.6-1.0 MPa | Heavy structures | Very good bearing | | Soft rock (shale) | 1-10 MPa | Bridge supports | Rock analysis needed | | Medium rock | 10-50 MPa | Tall buildings | High capacity | | Hard rock (granite) | 50-100+ MPa | Largest structures | Excellent foundation |
Design process: Site investigation → soil tests → pressure capacity → foundation design
Additional Unit Information
About Millimeter of Mercury (mmHg)
What is normal blood pressure in mmHg?
120/80 mmHg is considered normal adult blood pressure
120 mmHg (systolic):
- Pressure in arteries when heart beats/contracts
- Upper number in blood pressure reading
80 mmHg (diastolic):
- Pressure in arteries when heart rests between beats
- Lower number in blood pressure reading
Blood pressure categories (American Heart Association):
- Normal: <120/<80 mmHg
- Elevated: 120-129/<80 mmHg
- Stage 1 Hypertension: 130-139/80-89 mmHg
- Stage 2 Hypertension: ≥140/90 mmHg
- Hypertensive Crisis: >180/120 mmHg (seek emergency care)
How do I convert mmHg to PSI?
Formula: PSI = mmHg × 0.0193368
Examples:
- 120 mmHg = 2.32 PSI (systolic blood pressure)
- 80 mmHg = 1.55 PSI (diastolic blood pressure)
- 760 mmHg = 14.7 PSI (atmospheric pressure)
- 100 mmHg = 1.93 PSI
- 10 mmHg = 0.19 PSI
Why is blood pressure measured in mmHg?
Historical: Early sphygmomanometers (blood pressure cuffs) used mercury columns Standardization: Established globally since early 1900s Accuracy: Mercury barometers very accurate and reliable Consistency: Changing units would cause confusion in medical field Universal: Understood by doctors, nurses, patients worldwide
Modern devices: Digital monitors still display mmHg for consistency, even though they don't use actual mercury.
Why not change?:
- Medical literature, guidelines all use mmHg
- Training and education based on mmHg
- Patient familiarity (everyone knows "120 over 80")
- Risk of errors during transition period
What is the difference between mmHg and Torr?
Virtually identical: 1 mmHg ≈ 1 Torr (difference < 0.000015%)
mmHg (Millimeter of Mercury):
- Based on mercury density at 0°C, standard gravity
- Slightly temperature/gravity dependent
- Preferred in medicine (blood pressure)
Torr:
- Defined as exactly 1/760 atmosphere
- Independent of mercury properties
- Preferred in vacuum technology, physics
Practical usage: Treat them as equal—difference is negligible for all practical purposes.
Conversion: 1 mmHg = 1.000000142 Torr (effectively 1:1)
How many mmHg is 1 atmosphere?
1 atm = 760 mmHg (exactly, by definition)
This is the height of mercury column supported by atmospheric pressure at sea level.
Examples:
- 0.5 atm = 380 mmHg
- 1 atm = 760 mmHg (sea level)
- 2 atm = 1,520 mmHg (diving 10m deep)
- 3 atm = 2,280 mmHg (diving 20m deep)
Altitude effect:
- Sea level: 760 mmHg
- Denver (1,609m): ~630 mmHg
- La Paz, Bolivia (3,640m): ~480 mmHg
- Mount Everest (8,848m): ~253 mmHg
Atmosphere to mmHg converter →
Will medicine switch from mmHg to kPa?
Slow transition, likely decades away (if ever)
Current status:
- Still dominant: Most medical equipment worldwide uses mmHg
- Some countries transitioning: Australia, Canada partially adopted kPa
- Dual display: Modern monitors often show both mmHg and kPa
- Guidelines: International medical guidelines still primarily use mmHg
Challenges to switching:
- Familiarity: "120/80" universally understood
- Education: Medical training globally uses mmHg
- Communication: Doctor-patient communication simpler with mmHg
- Standards: Hypertension thresholds defined in mmHg
- Risk: Potential for medication errors during transition
Conversion: 120/80 mmHg = 16.0/10.7 kPa (less intuitive)
Prediction: mmHg likely to persist in medicine for foreseeable future despite SI adoption elsewhere.
About Megapascal (MPa)
How do I convert MPa to PSI?
Formula: PSI = MPa × 145.038
Examples:
- 1 MPa = 145 PSI
- 10 MPa = 1,450 PSI (car brakes)
- 20 MPa = 2,900 PSI (hydraulic tools)
- 30 MPa = 4,350 PSI (scuba tank)
- 70 MPa = 10,153 PSI (H2 fuel tank)
What is concrete strength in MPa?
Residential concrete: 20-32 MPa (2,900-4,650 PSI)
- Footings/slabs: 20-25 MPa
- Foundation walls: 25-30 MPa
- Driveway: 25-32 MPa
Commercial concrete: 30-50 MPa
- Floors: 30-35 MPa
- Beams/columns: 35-50 MPa
High-strength: 50-100+ MPa
- High-rise buildings: 50-80 MPa
- Bridges: 60-100 MPa
- Special applications: 100-150 MPa
Conversion: Divide PSI by 145 to get MPa (e.g., 3,000 PSI ≈ 21 MPa)
How do I convert MPa to bar?
Formula: bar = MPa × 10
Examples:
- 0.1 MPa = 1 bar
- 1 MPa = 10 bar
- 2 MPa = 20 bar
- 10 MPa = 100 bar
- 20 MPa = 200 bar (scuba tank)
What is a typical hydraulic system pressure?
Low pressure: 7-14 MPa (1,000-2,000 PSI)
- Automotive power steering: 8-12 MPa
- Light hydraulic lifts: 7-10 MPa
Medium pressure: 14-21 MPa (2,000-3,000 PSI)
- Construction equipment: 20-25 MPa
- Agricultural machinery: 14-20 MPa
- Automotive brakes: 10-15 MPa
High pressure: 21-35 MPa (3,000-5,000 PSI)
- Industrial presses: 25-35 MPa
- Heavy construction: 30-35 MPa
- Excavators: 30-35 MPa
Very high pressure: >35 MPa (>5,000 PSI)
- Hydraulic jacks: 50-70 MPa
- Specialized industrial: 70-100 MPa
Why use MPa instead of PSI for material strength?
SI standard: International engineering uses MPa universally Simpler numbers: 400 MPa vs 58,000 PSI Scientific: Consistent with stress calculations (force/area in N/m²) Global: Specifications understood worldwide
Conversion: PSI ÷ 145 ≈ MPa (or PSI × 0.00689 = MPa)
Example: Steel yield strength
- As MPa: 250-400 MPa (easy)
- As PSI: 36,000-58,000 PSI (unwieldy)
Conversion Table: Millimeter of Mercury to Megapascal
| Millimeter of Mercury (mmHg) | Megapascal (MPa) |
|---|---|
| 0.5 | 0 |
| 1 | 0 |
| 1.5 | 0 |
| 2 | 0 |
| 5 | 0.001 |
| 10 | 0.001 |
| 25 | 0.003 |
| 50 | 0.007 |
| 100 | 0.013 |
| 250 | 0.033 |
| 500 | 0.067 |
| 1,000 | 0.133 |
People Also Ask
How do I convert Millimeter of Mercury to Megapascal?
To convert Millimeter of Mercury to Megapascal, enter the value in Millimeter of Mercury in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our pressure converter page to convert between other units in this category.
Learn more →What is the conversion factor from Millimeter of Mercury to Megapascal?
The conversion factor depends on the specific relationship between Millimeter of Mercury and Megapascal. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.
Can I convert Megapascal back to Millimeter of Mercury?
Yes! You can easily convert Megapascal back to Millimeter of Mercury by using the swap button (⇌) in the calculator above, or by visiting our Megapascal to Millimeter of Mercury converter page. You can also explore other pressure conversions on our category page.
Learn more →What are common uses for Millimeter of Mercury and Megapascal?
Millimeter of Mercury and Megapascal are both standard units used in pressure measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our pressure converter for more conversion options.
For more pressure conversion questions, visit our FAQ page or explore our conversion guides.
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📚 How to Convert Units
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⚖️ Metric vs Imperial
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All Pressure Conversions
Other Pressure Units and Conversions
Explore other pressure units and their conversion options:
- Pascal (Pa) • Millimeter of Mercury to Pascal
- Kilopascal (kPa) • Millimeter of Mercury to Kilopascal
- Hectopascal (hPa) • Millimeter of Mercury to Hectopascal
- Bar (bar) • Millimeter of Mercury to Bar
- Millibar (mbar) • Millimeter of Mercury to Millibar
- Atmosphere (atm) • Millimeter of Mercury to Atmosphere
- Technical Atmosphere (at) • Millimeter of Mercury to Technical Atmosphere
- Torr (Torr) • Millimeter of Mercury to Torr
- Inch of Mercury (inHg) • Millimeter of Mercury to Inch of Mercury
- Pound per Square Inch (psi) • Millimeter of Mercury to Pound per Square Inch
Verified Against Authority Standards
All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.
National Institute of Standards and Technology — Fundamental physical constants and unit conversions
Bureau International des Poids et Mesures — International System of Units (SI) definitions and standards
International Organization for Standardization — Quantities and units international standards series
Last verified: February 19, 2026