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Pressure Converter

Convert PSI to bar, kPa to mmHg, atm to kPa & 15+ pressure units instantly. Used by engineers, mechanics & medical pros. Free, no sign-up, displays up to 15 decimals.

Last revised 29 September 2026

By Team GlobalCalqulate · About our editorial standards

Pressure Conversion

Value

Enter the pressure value to convert.

From Unit

Select the unit you want to convert from.

To Unit

Select the unit you want to convert to.

Decimal Places

Number of decimal places for the result (max 15).

Disclaimer: This converter uses exact, internationally defined conversion factors, but results are for general reference only. Pressure readings for safety-critical systems — tire inflation, boiler and pipeline ratings, hydraulic equipment — should be verified against the equipment manufacturer's own specifications and gauge tolerances before use. Full disclaimer.

Sources & methodology

Formula:: Two-step conversion through a base unit
Reference:: Bureau International des Poids et Mesures (BIPM)
Content last updated:: September 2026
Scheduled re-verification:: September 2027

Calculation type: Exact calculation. Figures are taken from Bureau International des Poids et Mesures (BIPM) and National Institute of Standards and Technology (NIST) — see sources below.

Formula & methodology

Formula used

Two-step conversion through a base unit

value_out = (value_in × factor_in→the pascal) ÷ factor_out→the pascal

Every pressure unit is defined as a multiple of the pascal. A conversion goes in to the pascal and back out again, so one factor per unit covers every possible pair rather than needing a factor for each combination.

Variable definitions

Symbol	Meaning	Unit
factor	Conversion factor. how many pascals one unit represents	Pa

Step-by-step calculation

1. Choose the unit you have
The value is converted to pascals first.
2. Choose the unit you want
Pascals are converted out to the target unit.

Limitations

Gauge pressure and absolute pressure are different baselines. Tyre and process gauges usually read gauge pressure (relative to atmospheric); this converter changes units only and does not shift between the two.
Fluid-column units (mmHg, inH2O, ftH2O) depend on the fluid density and gravity assumed. Standard conventional values are used here.
Rounding is applied to the displayed figure only; the conversion itself runs at full floating-point precision. Chaining many rounded conversions by hand will drift, but a single conversion here will not.

This page is educational. It converts between units using the defined or standard factors shown above, so the arithmetic is exact to the precision displayed — but a converted value is only as good as the measurement behind it, and some units are defined only under stated conditions. Where a conversion is safety-critical or contractual, check it against the governing standard rather than relying on this page.

Sources & references

The International System of Units (SI Brochure, 9th edition) — pascal as the SI derived unit of pressure — Bureau International des Poids et Mesures (BIPM)
NIST Guide for the Use of the SI — Appendix B conversion factors (PSI, atm, mmHg, inH₂O, ftH₂O, kgf/cm²) — National Institute of Standards and Technology (NIST)
Standard atmosphere fixed at exactly 101,325 Pa — National Institute of Standards and Technology (NIST)

Verified against internationally recognized measurement standards (BIPM SI Brochure and NIST SP 811 Appendix B). PSI, atm, and the SI-prefixed pascal units are exact by definition; mmHg, inH₂O, ftH₂O, and kgf/cm² use the standard 'conventional' water/mercury density and standard gravity (9.80665 m/s²) fixed by international agreement, so all conversions on this page are exact to the precision NIST publishes, not empirical measurements. Standards review: August 2026.

Help & FAQs

Frequently Asked Questions

Clear answers to common questions to help you use this calculator confidently.

How do I convert PSI to bar?

Tap to view the answer

Multiply PSI by 0.0689476. Example: 30 PSI × 0.0689476 ≈ 2.07 bar. PSI is standard in the USA and UK; bar is widely used in Europe and most international industrial contexts.

What is normal tire pressure in PSI, bar, and kPa?

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Most passenger car tires run 30-35 PSI, which is about 2.0-2.4 bar or 200-240 kPa. Always use the pressure printed on your vehicle's door jamb or manual, not a generic figure, since the correct value varies by vehicle and load.

What is the difference between gauge pressure and absolute pressure?

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Absolute pressure is measured relative to a perfect vacuum (0 Pa). Gauge pressure is measured relative to ambient atmospheric pressure, so a gauge reading of 0 means the system is at atmospheric pressure, not a vacuum. To convert gauge to absolute, add about 101.325 kPa (14.696 PSI) at sea level.

What pressure unit is used for blood pressure?

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Millimeters of mercury (mmHg) is the clinical standard for blood pressure worldwide. Normal resting blood pressure is defined as 120/80 mmHg. To convert to kPa, multiply by 0.133322: 120 mmHg ≈ 16.0 kPa.

Is this pressure converter accurate for engineering applications?

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Yes — conversion factors are exact SI/NIST definitions, so results are precise to the decimal places you choose. For safety-critical work (pressure vessel design, medical equipment calibration, tire/hydraulic systems), verify against the equipment's own specifications and consult a qualified engineer.

Need more help? Contact support or email globalcalqulate@gmail.com

We typically reply within 24–48 hours.

More converters

All converters

From	To	Conversion
1 atm	101.325 kPa	101.325
1 atm	14.696 psi	14.696
1 atm	760 mmHg	760
1 bar	100 kPa	100
1 bar	14.504 psi	14.504
1 psi	6.895 kPa	6.895
1 kPa	0.1450 psi	0.1450
1 MPa	145.04 psi	145.04
1 Torr	1 mmHg	1
1 Torr	133.3 Pa	133.3

From	To	Conversion
1 atm	101.325 kPa	101.325
1 atm	14.696 psi	14.696
1 atm	760 mmHg	760
1 bar	100 kPa	100
1 bar	14.504 psi	14.504
1 psi	6.895 kPa	6.895
1 kPa	0.1450 psi	0.1450
1 MPa	145.04 psi	145.04
1 Torr	1 mmHg	1
1 Torr	133.3 Pa	133.3

Calculator inputs

Pressure Conversion

Your results

Sources & methodology

Formula & methodology

Formula used

Two-step conversion through a base unit

Variable definitions

Step-by-step calculation

Limitations

Sources & references

How do I convert PSI to bar?

What is normal tire pressure in PSI, bar, and kPa?

What is the difference between gauge pressure and absolute pressure?

What pressure unit is used for blood pressure?

Is this pressure converter accurate for engineering applications?

Related calculators

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Calculator inputs

Pressure Conversion

Your results

Sources & methodology

How to Use This Calculator

Example: Convert 32 PSI to bar

Common Pressure Conversions

Understanding Your Results

Key Tips

Understanding Pressure Units

What is Pressure?

Common Pressure Units

Gauge vs. Absolute Pressure

Formula & methodology

Formula used

Two-step conversion through a base unit

Variable definitions

Step-by-step calculation

Limitations

Sources & references

How to Use This Calculator

Example: Convert 32 PSI to bar

Common Pressure Conversions

Understanding Your Results

Key Tips

Understanding Pressure Units

What is Pressure?

Common Pressure Units

Gauge vs. Absolute Pressure