Authoritative definitions of the International System of Units and SI prefixes.
Dedicated unit pair
Millimetres of mercury to Pounds per square inch
Convert mmHg to psi instantly, then review the formula, assumptions, and rounding guidance.
Pressure & stressInstant result
Decimals
Formula result = input × 133.3223874 ÷ 6894.757293. 1 mmHg = 0.0193 psi
Common examples
One value, several units
Pascals133.3224 Pa
Kilopascals0.1333 kPa
Megapascals0.0001 MPa
Bar0.0013 bar
Atmospheres0.0013 atm
Pounds per square inch0.0193 psi
Conversion table
| mmHg | psi |
|---|---|
| 1 mmHg | 0.0193 psi |
| 2 mmHg | 0.0387 psi |
| 5 mmHg | 0.0967 psi |
| 10 mmHg | 0.1934 psi |
| 25 mmHg | 0.4834 psi |
| 50 mmHg | 0.9668 psi |
| 100 mmHg | 1.9337 psi |
Conversion chart
1 mmHg0.0193 psi
5 mmHg0.0967 psi
10 mmHg0.1934 psi
25 mmHg0.4834 psi
50 mmHg0.9668 psi
Worked example
Standard atmosphere is 101,325 pascals.
Unit definition
Millimetres of mercury (mmHg) One millimetres of mercury equals 133.3223874 pascal.
Unit history
Millimetres of mercury is represented here using its modern SI definition or an internationally accepted relationship to an SI base unit.
Step by step
1. Parse the value, including fractions.
2. Convert mmHg to pascal.
3. Convert the base value to psi and apply your display precision.
Understand the result before using it
Millimetres of mercury to Pounds per square inch converts a value measured in Millimetres of mercury (mmHg) into the equivalent value in Pounds per square inch (psi). The numerical value changes because the size and definition of the selected unit changes; the underlying quantity does not.
Calculated result
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.
Formula, assumptions, and example
Formula
result = input × 133.3223874 ÷ 6894.757293
Assumptions
- Millimetres of mercury and Pounds per square inch represent the same pressure & stress quantity.
- The input is expressed in mmHg; the output is expressed in psi.
- The unit definitions and conventional relationship shown on this page apply.
Worked example
1 mmHg = 0.0193367774578 psi. For another value, apply the same relationship and round only to the precision your source measurement supports.
When to use it
Good uses
- Read a mmHg measurement in a document that expects psi.
- Compare a millimetres of mercury value with a value reported in pounds per square inch.
- Check the mmHg-to-psi arithmetic before copying the result into another calculation.
Limitations
Common mistakes to avoid
- Do not confuse mmHg with another unit that has a similar name or symbol.
- Round the output to a precision justified by the original measurement.
- Verify safety-critical, regulated, laboratory, and contractual conversions against the controlling standard.
Sources and further reading
These references explain the underlying standards or provide authoritative context. Your own contract, institution, clinician, product documentation, local code, or governing standard may be the controlling source.
Guidance on unit names, symbols, conversions, and numerical presentation.
Questions about this calculation
How do I convert Millimetres of mercury to Pounds per square inch?
result = input × 133.3223874 ÷ 6894.757293 Using the displayed relationship, 1 mmHg equals 0.0193367774578 psi.
How many Pounds per square inch are in one Millimetres of mercury?
One Millimetres of mercury is 0.0193367774578 Pounds per square inch. The displayed digits may be rounded.
Can I reverse the mmHg to psi conversion?
Yes. Swap the source and target units in the converter. The reverse relationship converts psi back to mmHg.
Is the Millimetres of mercury to Pounds per square inch result exact?
The conversion follows the displayed unit relationship. Display rounding can hide additional digits, and measured inputs cannot become more accurate merely by changing units.