Millimeter of Mercury to Inch of Mercury Converter

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

mmHg to PSI converter →

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)

mmHg to Torr converter →

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.