Millimeter of Mercury to Torr Converter
Convert millimeters of mercury to torr with our free online pressure converter.
Quick Answer
1 Millimeter of Mercury = 1 torr
Formula: Millimeter of Mercury Γ conversion factor = Torr
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 Torr Calculator
How to Use the Millimeter of Mercury to Torr Calculator:
- Enter the value you want to convert in the 'From' field (Millimeter of Mercury).
- The converted value in Torr will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Pressure category.
- Click the swap button (β) to reverse the conversion direction.
How to Convert Millimeter of Mercury to Torr: Step-by-Step Guide
Converting Millimeter of Mercury to Torr involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
Torr = mmHg Γ 1Example Calculation:
1 mmHg = 1 Torr
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.
Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.
Need to convert to other pressure units?
View all Pressure conversions βWhat is a Millimeter of Mercury and a Torr?
1 mmHg = 133.322 Pa = 0.133 kPa β 1 Torr (0.000015% difference) = 1/760 atm = 0.0193 PSI
Standard relationships:
- 760 mmHg = 1 atmosphere (standard pressure)
- 1 mmHg β 1 Torr (virtually identical)
- 1 mmHg = 1.333 mbar
1 Torr = 1/760 atm (exactly) = 133.322 Pa = 1.333 mbar β 1 mmHg (0.000015% difference)
Key relationships:
- 760 Torr = 1 atmosphere (exactly)
- 1 Torr β 1 mmHg (virtually identical)
- 1 mTorr = 0.001 Torr (millitorr)
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 Torr belongs to the imperial/US customary system.
Common Uses and Applications: millimeters of mercury vs torr
Explore the typical applications for both Millimeter of Mercury (imperial/US) and Torr (imperial/US) to understand their common contexts.
Common Uses for millimeters of mercury
Medicine: Blood pressure (universal standard), intracranial pressure, intraocular pressure. Meteorology: Barometric pressure (historical, now mostly hPa/mbar). Laboratory: Gas pressures, vacuum measurements, vapor pressure. Aviation: Altimeter settings (older aircraft, some regions).
When to Use torr
Vacuum Technology: High vacuum pumps, vacuum chambers, thin-film deposition. Physics Laboratories: Pressure measurement in evacuated systems. Chemistry: Vapor pressure measurements, distillation processes. Medicine: Blood pressure (often interchangeable with mmHg).
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: β₯140/90 mmHg
- Hypertensive Crisis: >180/120 mmHg (seek emergency care)
How do I convert mmHg to PSI?
Formula: PSI = mmHg Γ 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 β 1 Torr (difference < 0.000015%)
mmHg (Millimeter of Mercury):
- Based on mercury density at 0Β°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 equalβdifference 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 β
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 Torr (Torr)
What is the difference between Torr and mmHg?
Almost identical: 1 Torr β 1 mmHg (difference < 0.000015%)
Torr: Defined as exactly 1/760 atmosphere (by definition) mmHg: Based on mercury density at 0Β°C and standard gravity
Practical usage:
- Vacuum technology: Prefers Torr (more precise definition)
- Medicine: Prefers mmHg (traditional, familiar)
- Chemistry: Uses both interchangeably
Conversion: For all practical purposes, treat them as equal.
How many torr in 1 atmosphere?
1 atm = 760 Torr (exactly, by definition)
Examples:
- 2 atm = 1,520 Torr
- 0.5 atm = 380 Torr
- 0.001 atm = 0.76 Torr
- 10β»βΆ atm = 0.00076 Torr = 0.76 mTorr (millitorr)
Atmosphere to Torr converter β
How do I convert Torr to PSI?
Formula: PSI = Torr Γ 0.0193368
Examples:
- 760 Torr = 14.7 PSI (1 atmosphere)
- 120 Torr = 2.32 PSI (systolic blood pressure)
- 80 Torr = 1.55 PSI (diastolic blood pressure)
- 1 Torr = 0.0193 PSI
- 0.001 Torr = 0.0000193 PSI
How do I convert Torr to Pascals?
Formula: Pa = Torr Γ 133.322
Examples:
- 1 Torr = 133.322 Pa = 0.133 kPa
- 760 Torr = 101,325 Pa = 101.325 kPa (1 atm)
- 0.001 Torr (1 mTorr) = 0.133 Pa
- 10β»βΆ Torr = 0.000133 Pa
Why use Torr instead of mmHg in vacuum technology?
Torr advantages:
- Exact definition: 1/760 atm (no ambiguity)
- Independent: Not dependent on mercury properties
- Standard: Agreed upon by vacuum scientists
- Precision: Better defined for scientific work
mmHg issues:
- Temperature dependent: Mercury density varies
- Gravity dependent: Varies slightly with location
- Less precise: For ultra-high vacuum measurements
In practice: Both work fine for most applications, but Torr is preferred in vacuum physics and engineering.
Conversion Table: Millimeter of Mercury to Torr
| Millimeter of Mercury (mmHg) | Torr (Torr) |
|---|---|
| 0.5 | 0.5 |
| 1 | 1 |
| 1.5 | 1.5 |
| 2 | 2 |
| 5 | 5 |
| 10 | 10 |
| 25 | 25 |
| 50 | 50 |
| 100 | 100 |
| 250 | 250 |
| 500 | 500 |
| 1,000 | 1,000 |
People Also Ask
How do I convert Millimeter of Mercury to Torr?
To convert Millimeter of Mercury to Torr, 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 βWhat is the conversion factor from Millimeter of Mercury to Torr?
The conversion factor depends on the specific relationship between Millimeter of Mercury and Torr. 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 Torr back to Millimeter of Mercury?
Yes! You can easily convert Torr back to Millimeter of Mercury by using the swap button (β) in the calculator above, or by visiting our Torr to Millimeter of Mercury converter page. You can also explore other pressure conversions on our category page.
Learn more βWhat are common uses for Millimeter of Mercury and Torr?
Millimeter of Mercury and Torr 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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All Pressure Conversions
Other Pressure Units and Conversions
Explore other pressure units and their conversion options:
- Pascal (Pa) β’ Millimeter of Mercury to Pascal
- Kilopascal (kPa) β’ Millimeter of Mercury to Kilopascal
- Megapascal (MPa) β’ Millimeter of Mercury to Megapascal
- Hectopascal (hPa) β’ Millimeter of Mercury to Hectopascal
- Bar (bar) β’ Millimeter of Mercury to Bar
- Millibar (mbar) β’ Millimeter of Mercury to Millibar
- Atmosphere (atm) β’ Millimeter of Mercury to Atmosphere
- Technical Atmosphere (at) β’ Millimeter of Mercury to Technical Atmosphere
- Inch of Mercury (inHg) β’ Millimeter of Mercury to Inch of Mercury
- Pound per Square Inch (psi) β’ 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 β Fundamental physical constants and unit conversions
Bureau International des Poids et Mesures β International System of Units (SI) definitions and standards
International Organization for Standardization β Quantities and units international standards series
Last verified: December 3, 2025